Merge branch 'develop' into neilj/room_capabilities

2024-12-25 14:39:22 -05:00 · 2019-01-30 10:28:08 +00:00 · 2019-01-30 10:28:08 +00:00 · ee4df7fd7a
commit ee4df7fd7a
parent c5a0f82cca 457fbfaf22
123 changed files with 2447 additions and 665 deletions
--- a/MANIFEST.in
+++ b/MANIFEST.in
@ -15,6 +15,7 @@ recursive-include docs *
 recursive-include scripts *
 recursive-include scripts-dev *
 recursive-include synapse *.pyi
+recursive-include tests *.pem
 recursive-include tests *.py

 recursive-include synapse/res *
--- a/UPGRADE.rst
+++ b/UPGRADE.rst
@ -18,7 +18,7 @@ instructions that may be required are listed later in this document.

   .. code:: bash

-       pip install --upgrade --process-dependency-links matrix-synapse
+       pip install --upgrade matrix-synapse

       # restart synapse
       synctl restart
--- a/changelog.d/4405.bugfix
+++ b/changelog.d/4405.bugfix
@ -0,0 +1 @@
+Fix bug when rejecting remote invites
--- a/changelog.d/4408.feature
+++ b/changelog.d/4408.feature
@ -0,0 +1 @@
+Implement MSC1708 (.well-known routing for server-server federation)
--- a/changelog.d/4408.misc
+++ b/changelog.d/4408.misc
@ -1 +0,0 @@
-Refactor 'sign_request' as 'build_auth_headers'
--- a/changelog.d/4409.feature
+++ b/changelog.d/4409.feature
@ -0,0 +1 @@
+Implement MSC1708 (.well-known routing for server-server federation)
--- a/changelog.d/4409.misc
+++ b/changelog.d/4409.misc
@ -1 +0,0 @@
-Remove redundant federation connection wrapping code
--- a/changelog.d/4412.bugfix
+++ b/changelog.d/4412.bugfix
@ -0,0 +1 @@
+Copy over whether a room is a direct message and any associated room tags on room upgrade.
--- a/changelog.d/4415.feature
+++ b/changelog.d/4415.feature
@ -0,0 +1 @@
+Search now includes results from predecessor rooms after a room upgrade.
--- a/changelog.d/4426.feature
+++ b/changelog.d/4426.feature
@ -0,0 +1 @@
+Implement MSC1708 (.well-known routing for server-server federation)
--- a/changelog.d/4426.misc
+++ b/changelog.d/4426.misc
@ -1 +0,0 @@
-Remove redundant SynapseKeyClientProtocol magic
--- a/changelog.d/4427.feature
+++ b/changelog.d/4427.feature
@ -0,0 +1 @@
+Implement MSC1708 (.well-known routing for server-server federation)
--- a/changelog.d/4427.misc
+++ b/changelog.d/4427.misc
@ -1 +0,0 @@
-Refactor and cleanup for SRV record lookup
--- a/changelog.d/4428.feature
+++ b/changelog.d/4428.feature
@ -0,0 +1 @@
+Implement MSC1708 (.well-known routing for server-server federation)
--- a/changelog.d/4428.misc
+++ b/changelog.d/4428.misc
@ -1 +0,0 @@
-Move SRV logic into the Agent layer
--- a/changelog.d/4437.misc
+++ b/changelog.d/4437.misc
@ -0,0 +1 @@
+Add infrastructure to support different event formats
--- a/changelog.d/4447.misc
+++ b/changelog.d/4447.misc
@ -0,0 +1 @@
+Add infrastructure to support different event formats
--- a/changelog.d/4448.misc
+++ b/changelog.d/4448.misc
@ -0,0 +1 @@
+Add infrastructure to support different event formats
--- a/changelog.d/4464.feature
+++ b/changelog.d/4464.feature
@ -0,0 +1 @@
+Implement MSC1708 (.well-known routing for server-server federation)
--- a/changelog.d/4464.misc
+++ b/changelog.d/4464.misc
@ -1 +0,0 @@
-Move SRV logic into the Agent layer
--- a/changelog.d/4466.misc
+++ b/changelog.d/4466.misc
@ -0,0 +1 @@
+Synapse will now take advantage of native UPSERT functionality in PostgreSQL 9.5+ and SQLite 3.24+.
--- a/changelog.d/4468.feature
+++ b/changelog.d/4468.feature
@ -0,0 +1 @@
+Implement MSC1708 (.well-known routing for server-server federation)
--- a/changelog.d/4470.misc
+++ b/changelog.d/4470.misc
@ -0,0 +1 @@
+Add infrastructure to support different event formats
--- a/changelog.d/4471.misc
+++ b/changelog.d/4471.misc
@ -0,0 +1 @@
+ Synapse will now take advantage of native UPSERT functionality in PostgreSQL 9.5+ and SQLite 3.24+.
--- a/changelog.d/4476.misc
+++ b/changelog.d/4476.misc
@ -0,0 +1 @@
+Fix quoting for allowed_local_3pids example config
--- a/changelog.d/4477.misc
+++ b/changelog.d/4477.misc
@ -0,0 +1 @@
+Synapse will now take advantage of native UPSERT functionality in PostgreSQL 9.5+ and SQLite 3.24+.
--- a/changelog.d/4481.misc
+++ b/changelog.d/4481.misc
@ -0,0 +1 @@
+Add infrastructure to support different event formats
--- a/changelog.d/4482.misc
+++ b/changelog.d/4482.misc
@ -0,0 +1 @@
+Add infrastructure to support different event formats
--- a/changelog.d/4483.feature
+++ b/changelog.d/4483.feature
@ -0,0 +1 @@
+Add support for room version 3
--- a/changelog.d/4485.misc
+++ b/changelog.d/4485.misc
@ -0,0 +1 @@
+Remove deprecated --process-dependency-links option from UPGRADE.rst
--- a/changelog.d/4486.bugfix
+++ b/changelog.d/4486.bugfix
@ -0,0 +1 @@
+Workaround for login error when using both LDAP and internal authentication.
--- a/changelog.d/4487.feature
+++ b/changelog.d/4487.feature
@ -0,0 +1 @@
+Implement MSC1708 (.well-known routing for server-server federation)
--- a/changelog.d/4488.feature
+++ b/changelog.d/4488.feature
@ -0,0 +1 @@
+Implement MSC1708 (.well-known routing for server-server federation)
--- a/changelog.d/4489.feature
+++ b/changelog.d/4489.feature
@ -0,0 +1 @@
+Implement MSC1708 (.well-known routing for server-server federation)
--- a/changelog.d/4492.feature
+++ b/changelog.d/4492.feature
@ -0,0 +1 @@
+ Synapse can now automatically provision TLS certificates via ACME (the protocol used by CAs like Let's Encrypt).
--- a/changelog.d/4493.misc
+++ b/changelog.d/4493.misc
@ -0,0 +1 @@
+Add infrastructure to support different event formats
--- a/changelog.d/4494.misc
+++ b/changelog.d/4494.misc
@ -0,0 +1 @@
+Add infrastructure to support different event formats
--- a/changelog.d/4496.misc
+++ b/changelog.d/4496.misc
@ -0,0 +1 @@
+Add infrastructure to support different event formats
--- a/changelog.d/4497.feature
+++ b/changelog.d/4497.feature
@ -0,0 +1 @@
+Implement MSC1708 (.well-known routing for server-server federation)
--- a/changelog.d/4498.misc
+++ b/changelog.d/4498.misc
@ -0,0 +1 @@
+Clarify documentation for the `public_baseurl` config param
--- a/changelog.d/4499.feature
+++ b/changelog.d/4499.feature
@ -0,0 +1 @@
+Add support for room version 3
--- a/changelog.d/4505.misc
+++ b/changelog.d/4505.misc
@ -0,0 +1 @@
+ Synapse will now take advantage of native UPSERT functionality in PostgreSQL 9.5+ and SQLite 3.24+.
--- a/changelog.d/4506.misc
+++ b/changelog.d/4506.misc
@ -0,0 +1 @@
+Make it possible to set the log level for tests via an environment variable
--- a/changelog.d/4507.misc
+++ b/changelog.d/4507.misc
@ -0,0 +1 @@
+Reduce the log level of linearizer lock acquirement to DEBUG.
--- a/changelog.d/4509.removal
+++ b/changelog.d/4509.removal
@ -0,0 +1 @@
+Synapse no longer generates self-signed TLS certificates when generating a configuration file.
--- a/changelog.d/4510.misc
+++ b/changelog.d/4510.misc
@ -0,0 +1 @@
+Add infrastructure to support different event formats
--- a/changelog.d/4511.feature
+++ b/changelog.d/4511.feature
@ -0,0 +1 @@
+Implement MSC1708 (.well-known routing for server-server federation)
--- a/changelog.d/4512.bugfix
+++ b/changelog.d/4512.bugfix
@ -0,0 +1 @@
+Fix a bug where setting a relative consent directory path would cause a crash.
--- a/changelog.d/4514.misc
+++ b/changelog.d/4514.misc
@ -0,0 +1 @@
+Add infrastructure to support different event formats
--- a/changelog.d/4515.feature
+++ b/changelog.d/4515.feature
@ -0,0 +1 @@
+Add support for room version 3
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@ -65,7 +65,7 @@ class Auth(object):
        register_cache("cache", "token_cache", self.token_cache)

    @defer.inlineCallbacks
-    def check_from_context(self, event, context, do_sig_check=True):
+    def check_from_context(self, room_version, event, context, do_sig_check=True):
        prev_state_ids = yield context.get_prev_state_ids(self.store)
        auth_events_ids = yield self.compute_auth_events(
            event, prev_state_ids, for_verification=True,
@ -74,12 +74,16 @@ class Auth(object):
        auth_events = {
            (e.type, e.state_key): e for e in itervalues(auth_events)
        }
-        self.check(event, auth_events=auth_events, do_sig_check=do_sig_check)
+        self.check(
+            room_version, event,
+            auth_events=auth_events, do_sig_check=do_sig_check,
+        )

-    def check(self, event, auth_events, do_sig_check=True):
+    def check(self, room_version, event, auth_events, do_sig_check=True):
        """ Checks if this event is correctly authed.

        Args:
+            room_version (str): version of the room
            event: the event being checked.
            auth_events (dict: event-key -> event): the existing room state.

@ -88,7 +92,9 @@ class Auth(object):
            True if the auth checks pass.
        """
        with Measure(self.clock, "auth.check"):
-            event_auth.check(event, auth_events, do_sig_check=do_sig_check)
+            event_auth.check(
+                room_version, event, auth_events, do_sig_check=do_sig_check
+            )

    @defer.inlineCallbacks
    def check_joined_room(self, room_id, user_id, current_state=None):
@ -544,17 +550,6 @@ class Auth(object):
        """
        return self.store.is_server_admin(user)

-    @defer.inlineCallbacks
-    def add_auth_events(self, builder, context):
-        prev_state_ids = yield context.get_prev_state_ids(self.store)
-        auth_ids = yield self.compute_auth_events(builder, prev_state_ids)
-
-        auth_events_entries = yield self.store.add_event_hashes(
-            auth_ids
-        )
-
-        builder.auth_events = auth_events_entries
-
    @defer.inlineCallbacks
    def compute_auth_events(self, event, current_state_ids, for_verification=False):
        if event.type == EventTypes.Create:
@ -571,7 +566,7 @@ class Auth(object):
        key = (EventTypes.JoinRules, "", )
        join_rule_event_id = current_state_ids.get(key)

-        key = (EventTypes.Member, event.user_id, )
+        key = (EventTypes.Member, event.sender, )
        member_event_id = current_state_ids.get(key)

        key = (EventTypes.Create, "", )
@ -621,7 +616,7 @@ class Auth(object):

        defer.returnValue(auth_ids)

-    def check_redaction(self, event, auth_events):
+    def check_redaction(self, room_version, event, auth_events):
        """Check whether the event sender is allowed to redact the target event.

        Returns:
@ -634,7 +629,7 @@ class Auth(object):
            AuthError if the event sender is definitely not allowed to redact
            the target event.
        """
-        return event_auth.check_redaction(event, auth_events)
+        return event_auth.check_redaction(room_version, event, auth_events)

    @defer.inlineCallbacks
    def check_can_change_room_list(self, room_id, user):
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@ -105,7 +105,6 @@ class RoomVersions(object):
    V1 = "1"
    V2 = "2"
    V3 = "3"
-    VDH_TEST = "vdh-test-version"
    STATE_V2_TEST = "state-v2-test"


@ -122,11 +121,26 @@ DEFAULT_ROOM_VERSION = RoomVersions.V1
 KNOWN_ROOM_VERSIONS = {
    RoomVersions.V1,
    RoomVersions.V2,
-    RoomVersions.VDH_TEST,
+    RoomVersions.V3,
    RoomVersions.STATE_V2_TEST,
    RoomVersions.V3,
 }

+
+class EventFormatVersions(object):
+    """This is an internal enum for tracking the version of the event format,
+    independently from the room version.
+    """
+    V1 = 1
+    V2 = 2
+
+
+KNOWN_EVENT_FORMAT_VERSIONS = {
+    EventFormatVersions.V1,
+    EventFormatVersions.V2,
+}
+
+
 ServerNoticeMsgType = "m.server_notice"
 ServerNoticeLimitReached = "m.server_notice.usage_limit_reached"

--- a/synapse/api/filtering.py
+++ b/synapse/api/filtering.py
@ -444,6 +444,20 @@ class Filter(object):
    def include_redundant_members(self):
        return self.filter_json.get("include_redundant_members", False)

+    def with_room_ids(self, room_ids):
+        """Returns a new filter with the given room IDs appended.
+
+        Args:
+            room_ids (iterable[unicode]): The room_ids to add
+
+        Returns:
+            filter: A new filter including the given rooms and the old
+                    filter's rooms.
+        """
+        newFilter = Filter(self.filter_json)
+        newFilter.rooms += room_ids
+        return newFilter
+

 def _matches_wildcard(actual_value, filter_value):
    if filter_value.endswith("*"):
--- a/synapse/app/client_reader.py
+++ b/synapse/app/client_reader.py
@ -164,23 +164,23 @@ def start(config_options):

    database_engine = create_engine(config.database_config)

-    tls_server_context_factory = context_factory.ServerContextFactory(config)
-    tls_client_options_factory = context_factory.ClientTLSOptionsFactory(config)
-
    ss = ClientReaderServer(
        config.server_name,
        db_config=config.database_config,
-        tls_server_context_factory=tls_server_context_factory,
-        tls_client_options_factory=tls_client_options_factory,
        config=config,
        version_string="Synapse/" + get_version_string(synapse),
        database_engine=database_engine,
    )

    ss.setup()
-    ss.start_listening(config.worker_listeners)

    def start():
+        ss.config.read_certificate_from_disk()
+        ss.tls_server_context_factory = context_factory.ServerContextFactory(config)
+        ss.tls_client_options_factory = context_factory.ClientTLSOptionsFactory(
+            config
+        )
+        ss.start_listening(config.worker_listeners)
        ss.get_datastore().start_profiling()

    reactor.callWhenRunning(start)
--- a/synapse/app/event_creator.py
+++ b/synapse/app/event_creator.py
@ -185,23 +185,23 @@ def start(config_options):

    database_engine = create_engine(config.database_config)

-    tls_server_context_factory = context_factory.ServerContextFactory(config)
-    tls_client_options_factory = context_factory.ClientTLSOptionsFactory(config)
-
    ss = EventCreatorServer(
        config.server_name,
        db_config=config.database_config,
-        tls_server_context_factory=tls_server_context_factory,
-        tls_client_options_factory=tls_client_options_factory,
        config=config,
        version_string="Synapse/" + get_version_string(synapse),
        database_engine=database_engine,
    )

    ss.setup()
-    ss.start_listening(config.worker_listeners)

    def start():
+        ss.config.read_certificate_from_disk()
+        ss.tls_server_context_factory = context_factory.ServerContextFactory(config)
+        ss.tls_client_options_factory = context_factory.ClientTLSOptionsFactory(
+            config
+        )
+        ss.start_listening(config.worker_listeners)
        ss.get_datastore().start_profiling()

    reactor.callWhenRunning(start)
--- a/synapse/app/federation_reader.py
+++ b/synapse/app/federation_reader.py
@ -151,23 +151,23 @@ def start(config_options):

    database_engine = create_engine(config.database_config)

-    tls_server_context_factory = context_factory.ServerContextFactory(config)
-    tls_client_options_factory = context_factory.ClientTLSOptionsFactory(config)
-
    ss = FederationReaderServer(
        config.server_name,
        db_config=config.database_config,
-        tls_server_context_factory=tls_server_context_factory,
-        tls_client_options_factory=tls_client_options_factory,
        config=config,
        version_string="Synapse/" + get_version_string(synapse),
        database_engine=database_engine,
    )

    ss.setup()
-    ss.start_listening(config.worker_listeners)

    def start():
+        ss.config.read_certificate_from_disk()
+        ss.tls_server_context_factory = context_factory.ServerContextFactory(config)
+        ss.tls_client_options_factory = context_factory.ClientTLSOptionsFactory(
+            config
+        )
+        ss.start_listening(config.worker_listeners)
        ss.get_datastore().start_profiling()

    reactor.callWhenRunning(start)
--- a/synapse/app/federation_sender.py
+++ b/synapse/app/federation_sender.py
@ -183,24 +183,24 @@ def start(config_options):
    # Force the pushers to start since they will be disabled in the main config
    config.send_federation = True

-    tls_server_context_factory = context_factory.ServerContextFactory(config)
-    tls_client_options_factory = context_factory.ClientTLSOptionsFactory(config)
-
-    ps = FederationSenderServer(
+    ss = FederationSenderServer(
        config.server_name,
        db_config=config.database_config,
-        tls_server_context_factory=tls_server_context_factory,
-        tls_client_options_factory=tls_client_options_factory,
        config=config,
        version_string="Synapse/" + get_version_string(synapse),
        database_engine=database_engine,
    )

-    ps.setup()
-    ps.start_listening(config.worker_listeners)
+    ss.setup()

    def start():
-        ps.get_datastore().start_profiling()
+        ss.config.read_certificate_from_disk()
+        ss.tls_server_context_factory = context_factory.ServerContextFactory(config)
+        ss.tls_client_options_factory = context_factory.ClientTLSOptionsFactory(
+            config
+        )
+        ss.start_listening(config.worker_listeners)
+        ss.get_datastore().start_profiling()

    reactor.callWhenRunning(start)
    _base.start_worker_reactor("synapse-federation-sender", config)
--- a/synapse/app/frontend_proxy.py
+++ b/synapse/app/frontend_proxy.py
@ -241,23 +241,23 @@ def start(config_options):

    database_engine = create_engine(config.database_config)

-    tls_server_context_factory = context_factory.ServerContextFactory(config)
-    tls_client_options_factory = context_factory.ClientTLSOptionsFactory(config)
-
    ss = FrontendProxyServer(
        config.server_name,
        db_config=config.database_config,
-        tls_server_context_factory=tls_server_context_factory,
-        tls_client_options_factory=tls_client_options_factory,
        config=config,
        version_string="Synapse/" + get_version_string(synapse),
        database_engine=database_engine,
    )

    ss.setup()
-    ss.start_listening(config.worker_listeners)

    def start():
+        ss.config.read_certificate_from_disk()
+        ss.tls_server_context_factory = context_factory.ServerContextFactory(config)
+        ss.tls_client_options_factory = context_factory.ClientTLSOptionsFactory(
+            config
+        )
+        ss.start_listening(config.worker_listeners)
        ss.get_datastore().start_profiling()

    reactor.callWhenRunning(start)
--- a/synapse/app/media_repository.py
+++ b/synapse/app/media_repository.py
@ -151,23 +151,23 @@ def start(config_options):

    database_engine = create_engine(config.database_config)

-    tls_server_context_factory = context_factory.ServerContextFactory(config)
-    tls_client_options_factory = context_factory.ClientTLSOptionsFactory(config)
-
    ss = MediaRepositoryServer(
        config.server_name,
        db_config=config.database_config,
-        tls_server_context_factory=tls_server_context_factory,
-        tls_client_options_factory=tls_client_options_factory,
        config=config,
        version_string="Synapse/" + get_version_string(synapse),
        database_engine=database_engine,
    )

    ss.setup()
-    ss.start_listening(config.worker_listeners)

    def start():
+        ss.config.read_certificate_from_disk()
+        ss.tls_server_context_factory = context_factory.ServerContextFactory(config)
+        ss.tls_client_options_factory = context_factory.ClientTLSOptionsFactory(
+            config
+        )
+        ss.start_listening(config.worker_listeners)
        ss.get_datastore().start_profiling()

    reactor.callWhenRunning(start)
--- a/synapse/app/user_dir.py
+++ b/synapse/app/user_dir.py
@ -211,24 +211,24 @@ def start(config_options):
    # Force the pushers to start since they will be disabled in the main config
    config.update_user_directory = True

-    tls_server_context_factory = context_factory.ServerContextFactory(config)
-    tls_client_options_factory = context_factory.ClientTLSOptionsFactory(config)
-
-    ps = UserDirectoryServer(
+    ss = UserDirectoryServer(
        config.server_name,
        db_config=config.database_config,
-        tls_server_context_factory=tls_server_context_factory,
-        tls_client_options_factory=tls_client_options_factory,
        config=config,
        version_string="Synapse/" + get_version_string(synapse),
        database_engine=database_engine,
    )

-    ps.setup()
-    ps.start_listening(config.worker_listeners)
+    ss.setup()

    def start():
-        ps.get_datastore().start_profiling()
+        ss.config.read_certificate_from_disk()
+        ss.tls_server_context_factory = context_factory.ServerContextFactory(config)
+        ss.tls_client_options_factory = context_factory.ClientTLSOptionsFactory(
+            config
+        )
+        ss.start_listening(config.worker_listeners)
+        ss.get_datastore().start_profiling()

    reactor.callWhenRunning(start)

--- a/synapse/config/consent_config.py
+++ b/synapse/config/consent_config.py
@ -13,6 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.

+from os import path
+
+from synapse.config import ConfigError
+
 from ._base import Config

 DEFAULT_CONFIG = """\
@ -85,7 +89,15 @@ class ConsentConfig(Config):
        if consent_config is None:
            return
        self.user_consent_version = str(consent_config["version"])
-        self.user_consent_template_dir = consent_config["template_dir"]
+        self.user_consent_template_dir = self.abspath(
+            consent_config["template_dir"]
+        )
+        if not path.isdir(self.user_consent_template_dir):
+            raise ConfigError(
+                "Could not find template directory '%s'" % (
+                    self.user_consent_template_dir,
+                ),
+            )
        self.user_consent_server_notice_content = consent_config.get(
            "server_notice_content",
        )
--- a/synapse/config/registration.py
+++ b/synapse/config/registration.py
@ -84,11 +84,11 @@ class RegistrationConfig(Config):
        #
        # allowed_local_3pids:
        #     - medium: email
-        #       pattern: ".*@matrix\\.org"
+        #       pattern: '.*@matrix\\.org'
        #     - medium: email
-        #       pattern: ".*@vector\\.im"
+        #       pattern: '.*@vector\\.im'
        #     - medium: msisdn
-        #       pattern: "\\+44"
+        #       pattern: '\\+44'

        # If set, allows registration by anyone who also has the shared
        # secret, even if registration is otherwise disabled.
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@ -261,7 +261,7 @@ class ServerConfig(Config):
        # enter into the 'custom HS URL' field on their client. If you
        # use synapse with a reverse proxy, this should be the URL to reach
        # synapse via the proxy.
-        # public_baseurl: https://example.com:8448/
+        # public_baseurl: https://example.com/

        # Set the soft limit on the number of file descriptors synapse can use
        # Zero is used to indicate synapse should set the soft limit to the
--- a/synapse/config/tls.py
+++ b/synapse/config/tls.py
@ -15,6 +15,7 @@

 import logging
 import os
+import warnings
 from datetime import datetime
 from hashlib import sha256

@ -39,8 +40,8 @@ class TlsConfig(Config):
        self.acme_bind_addresses = acme_config.get("bind_addresses", ["127.0.0.1"])
        self.acme_reprovision_threshold = acme_config.get("reprovision_threshold", 30)

-        self.tls_certificate_file = os.path.abspath(config.get("tls_certificate_path"))
-        self.tls_private_key_file = os.path.abspath(config.get("tls_private_key_path"))
+        self.tls_certificate_file = self.abspath(config.get("tls_certificate_path"))
+        self.tls_private_key_file = self.abspath(config.get("tls_private_key_path"))
        self._original_tls_fingerprints = config["tls_fingerprints"]
        self.tls_fingerprints = list(self._original_tls_fingerprints)
        self.no_tls = config.get("no_tls", False)
@ -94,6 +95,16 @@ class TlsConfig(Config):
        """
        self.tls_certificate = self.read_tls_certificate(self.tls_certificate_file)

+        # Check if it is self-signed, and issue a warning if so.
+        if self.tls_certificate.get_issuer() == self.tls_certificate.get_subject():
+            warnings.warn(
+                (
+                    "Self-signed TLS certificates will not be accepted by Synapse 1.0. "
+                    "Please either provide a valid certificate, or use Synapse's ACME "
+                    "support to provision one."
+                )
+            )
+
        if not self.no_tls:
            self.tls_private_key = self.read_tls_private_key(self.tls_private_key_file)

@ -118,10 +129,11 @@ class TlsConfig(Config):
        return (
            """\
        # PEM encoded X509 certificate for TLS.
-        # You can replace the self-signed certificate that synapse
-        # autogenerates on launch with your own SSL certificate + key pair
-        # if you like.  Any required intermediary certificates can be
-        # appended after the primary certificate in hierarchical order.
+        # This certificate, as of Synapse 1.0, will need to be a valid
+        # and verifiable certificate, with a root that is available in
+        # the root store of other servers you wish to federate to. Any
+        # required intermediary certificates can be appended after the
+        # primary certificate in hierarchical order.
        tls_certificate_path: "%(tls_certificate_path)s"

        # PEM encoded private key for TLS
@ -183,40 +195,3 @@ class TlsConfig(Config):
    def read_tls_private_key(self, private_key_path):
        private_key_pem = self.read_file(private_key_path, "tls_private_key")
        return crypto.load_privatekey(crypto.FILETYPE_PEM, private_key_pem)
-
-    def generate_files(self, config):
-        tls_certificate_path = config["tls_certificate_path"]
-        tls_private_key_path = config["tls_private_key_path"]
-
-        if not self.path_exists(tls_private_key_path):
-            with open(tls_private_key_path, "wb") as private_key_file:
-                tls_private_key = crypto.PKey()
-                tls_private_key.generate_key(crypto.TYPE_RSA, 2048)
-                private_key_pem = crypto.dump_privatekey(
-                    crypto.FILETYPE_PEM, tls_private_key
-                )
-                private_key_file.write(private_key_pem)
-        else:
-            with open(tls_private_key_path) as private_key_file:
-                private_key_pem = private_key_file.read()
-                tls_private_key = crypto.load_privatekey(
-                    crypto.FILETYPE_PEM, private_key_pem
-                )
-
-        if not self.path_exists(tls_certificate_path):
-            with open(tls_certificate_path, "wb") as certificate_file:
-                cert = crypto.X509()
-                subject = cert.get_subject()
-                subject.CN = config["server_name"]
-
-                cert.set_serial_number(1000)
-                cert.gmtime_adj_notBefore(0)
-                cert.gmtime_adj_notAfter(10 * 365 * 24 * 60 * 60)
-                cert.set_issuer(cert.get_subject())
-                cert.set_pubkey(tls_private_key)
-
-                cert.sign(tls_private_key, 'sha256')
-
-                cert_pem = crypto.dump_certificate(crypto.FILETYPE_PEM, cert)
-
-                certificate_file.write(cert_pem)
--- a/synapse/crypto/event_signing.py
+++ b/synapse/crypto/event_signing.py
@ -23,14 +23,14 @@ from signedjson.sign import sign_json
 from unpaddedbase64 import decode_base64, encode_base64

 from synapse.api.errors import Codes, SynapseError
-from synapse.events.utils import prune_event
+from synapse.events.utils import prune_event, prune_event_dict

 logger = logging.getLogger(__name__)


 def check_event_content_hash(event, hash_algorithm=hashlib.sha256):
    """Check whether the hash for this PDU matches the contents"""
-    name, expected_hash = compute_content_hash(event, hash_algorithm)
+    name, expected_hash = compute_content_hash(event.get_pdu_json(), hash_algorithm)
    logger.debug("Expecting hash: %s", encode_base64(expected_hash))

    # some malformed events lack a 'hashes'. Protect against it being missing
@ -59,35 +59,70 @@ def check_event_content_hash(event, hash_algorithm=hashlib.sha256):
    return message_hash_bytes == expected_hash


-def compute_content_hash(event, hash_algorithm):
-    event_json = event.get_pdu_json()
-    event_json.pop("age_ts", None)
-    event_json.pop("unsigned", None)
-    event_json.pop("signatures", None)
-    event_json.pop("hashes", None)
-    event_json.pop("outlier", None)
-    event_json.pop("destinations", None)
+def compute_content_hash(event_dict, hash_algorithm):
+    """Compute the content hash of an event, which is the hash of the
+    unredacted event.

-    event_json_bytes = encode_canonical_json(event_json)
+    Args:
+        event_dict (dict): The unredacted event as a dict
+        hash_algorithm: A hasher from `hashlib`, e.g. hashlib.sha256, to use
+            to hash the event
+
+    Returns:
+        tuple[str, bytes]: A tuple of the name of hash and the hash as raw
+        bytes.
+    """
+    event_dict = dict(event_dict)
+    event_dict.pop("age_ts", None)
+    event_dict.pop("unsigned", None)
+    event_dict.pop("signatures", None)
+    event_dict.pop("hashes", None)
+    event_dict.pop("outlier", None)
+    event_dict.pop("destinations", None)
+
+    event_json_bytes = encode_canonical_json(event_dict)

    hashed = hash_algorithm(event_json_bytes)
    return (hashed.name, hashed.digest())


 def compute_event_reference_hash(event, hash_algorithm=hashlib.sha256):
+    """Computes the event reference hash. This is the hash of the redacted
+    event.
+
+    Args:
+        event (FrozenEvent)
+        hash_algorithm: A hasher from `hashlib`, e.g. hashlib.sha256, to use
+            to hash the event
+
+    Returns:
+        tuple[str, bytes]: A tuple of the name of hash and the hash as raw
+        bytes.
+    """
    tmp_event = prune_event(event)
-    event_json = tmp_event.get_pdu_json()
-    event_json.pop("signatures", None)
-    event_json.pop("age_ts", None)
-    event_json.pop("unsigned", None)
-    event_json_bytes = encode_canonical_json(event_json)
+    event_dict = tmp_event.get_pdu_json()
+    event_dict.pop("signatures", None)
+    event_dict.pop("age_ts", None)
+    event_dict.pop("unsigned", None)
+    event_json_bytes = encode_canonical_json(event_dict)
    hashed = hash_algorithm(event_json_bytes)
    return (hashed.name, hashed.digest())


-def compute_event_signature(event, signature_name, signing_key):
-    tmp_event = prune_event(event)
-    redact_json = tmp_event.get_pdu_json()
+def compute_event_signature(event_dict, signature_name, signing_key):
+    """Compute the signature of the event for the given name and key.
+
+    Args:
+        event_dict (dict): The event as a dict
+        signature_name (str): The name of the entity signing the event
+            (typically the server's hostname).
+        signing_key (syutil.crypto.SigningKey): The key to sign with
+
+    Returns:
+        dict[str, dict[str, str]]: Returns a dictionary in the same format of
+        an event's signatures field.
+    """
+    redact_json = prune_event_dict(event_dict)
    redact_json.pop("age_ts", None)
    redact_json.pop("unsigned", None)
    logger.debug("Signing event: %s", encode_canonical_json(redact_json))
@ -96,25 +131,25 @@ def compute_event_signature(event, signature_name, signing_key):
    return redact_json["signatures"]


-def add_hashes_and_signatures(event, signature_name, signing_key,
+def add_hashes_and_signatures(event_dict, signature_name, signing_key,
                              hash_algorithm=hashlib.sha256):
-    # if hasattr(event, "old_state_events"):
-    #     state_json_bytes = encode_canonical_json(
-    #         [e.event_id for e in event.old_state_events.values()]
-    #     )
-    #     hashed = hash_algorithm(state_json_bytes)
-    #     event.state_hash = {
-    #         hashed.name: encode_base64(hashed.digest())
-    #     }
+    """Add content hash and sign the event

-    name, digest = compute_content_hash(event, hash_algorithm=hash_algorithm)
+    Args:
+        event_dict (dict): The event to add hashes to and sign
+        signature_name (str): The name of the entity signing the event
+            (typically the server's hostname).
+        signing_key (syutil.crypto.SigningKey): The key to sign with
+        hash_algorithm: A hasher from `hashlib`, e.g. hashlib.sha256, to use
+            to hash the event
+    """

-    if not hasattr(event, "hashes"):
-        event.hashes = {}
-    event.hashes[name] = encode_base64(digest)
+    name, digest = compute_content_hash(event_dict, hash_algorithm=hash_algorithm)

-    event.signatures = compute_event_signature(
-        event,
+    event_dict.setdefault("hashes", {})[name] = encode_base64(digest)
+
+    event_dict["signatures"] = compute_event_signature(
+        event_dict,
        signature_name=signature_name,
        signing_key=signing_key,
    )
--- a/synapse/event_auth.py
+++ b/synapse/event_auth.py
@ -20,17 +20,25 @@ from signedjson.key import decode_verify_key_bytes
 from signedjson.sign import SignatureVerifyException, verify_signed_json
 from unpaddedbase64 import decode_base64

-from synapse.api.constants import KNOWN_ROOM_VERSIONS, EventTypes, JoinRules, Membership
+from synapse.api.constants import (
+    KNOWN_ROOM_VERSIONS,
+    EventFormatVersions,
+    EventTypes,
+    JoinRules,
+    Membership,
+    RoomVersions,
+)
 from synapse.api.errors import AuthError, EventSizeError, SynapseError
 from synapse.types import UserID, get_domain_from_id

 logger = logging.getLogger(__name__)


-def check(event, auth_events, do_sig_check=True, do_size_check=True):
+def check(room_version, event, auth_events, do_sig_check=True, do_size_check=True):
    """ Checks if this event is correctly authed.

    Args:
+        room_version (str): the version of the room
        event: the event being checked.
        auth_events (dict: event-key -> event): the existing room state.

@ -48,7 +56,6 @@ def check(event, auth_events, do_sig_check=True, do_size_check=True):

    if do_sig_check:
        sender_domain = get_domain_from_id(event.sender)
-        event_id_domain = get_domain_from_id(event.event_id)

        is_invite_via_3pid = (
            event.type == EventTypes.Member
@ -65,9 +72,13 @@ def check(event, auth_events, do_sig_check=True, do_size_check=True):
            if not is_invite_via_3pid:
                raise AuthError(403, "Event not signed by sender's server")

-        # Check the event_id's domain has signed the event
-        if not event.signatures.get(event_id_domain):
-            raise AuthError(403, "Event not signed by sending server")
+        if event.format_version in (EventFormatVersions.V1,):
+            # Only older room versions have event IDs to check.
+            event_id_domain = get_domain_from_id(event.event_id)
+
+            # Check the origin domain has signed the event
+            if not event.signatures.get(event_id_domain):
+                raise AuthError(403, "Event not signed by sending server")

    if auth_events is None:
        # Oh, we don't know what the state of the room was, so we
@ -167,7 +178,7 @@ def check(event, auth_events, do_sig_check=True, do_size_check=True):
        _check_power_levels(event, auth_events)

    if event.type == EventTypes.Redaction:
-        check_redaction(event, auth_events)
+        check_redaction(room_version, event, auth_events)

    logger.debug("Allowing! %s", event)

@ -421,7 +432,7 @@ def _can_send_event(event, auth_events):
    return True


-def check_redaction(event, auth_events):
+def check_redaction(room_version, event, auth_events):
    """Check whether the event sender is allowed to redact the target event.

    Returns:
@ -441,10 +452,16 @@ def check_redaction(event, auth_events):
    if user_level >= redact_level:
        return False

-    redacter_domain = get_domain_from_id(event.event_id)
-    redactee_domain = get_domain_from_id(event.redacts)
-    if redacter_domain == redactee_domain:
+    if room_version in (RoomVersions.V1, RoomVersions.V2,):
+        redacter_domain = get_domain_from_id(event.event_id)
+        redactee_domain = get_domain_from_id(event.redacts)
+        if redacter_domain == redactee_domain:
+            return True
+    elif room_version == RoomVersions.V3:
+        event.internal_metadata.recheck_redaction = True
        return True
+    else:
+        raise RuntimeError("Unrecognized room version %r" % (room_version,))

    raise AuthError(
        403,
--- a/synapse/events/init.py
+++ b/synapse/events/init.py
@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
+# Copyright 2019 New Vector Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@ -18,6 +19,9 @@ from distutils.util import strtobool

 import six

+from unpaddedbase64 import encode_base64
+
+from synapse.api.constants import KNOWN_ROOM_VERSIONS, EventFormatVersions, RoomVersions
 from synapse.util.caches import intern_dict
 from synapse.util.frozenutils import freeze

@ -41,8 +45,13 @@ class _EventInternalMetadata(object):
    def is_outlier(self):
        return getattr(self, "outlier", False)

-    def is_invite_from_remote(self):
-        return getattr(self, "invite_from_remote", False)
+    def is_out_of_band_membership(self):
+        """Whether this is an out of band membership, like an invite or an invite
+        rejection. This is needed as those events are marked as outliers, but
+        they still need to be processed as if they're new events (e.g. updating
+        invite state in the database, relaying to clients, etc).
+        """
+        return getattr(self, "out_of_band_membership", False)

    def get_send_on_behalf_of(self):
        """Whether this server should send the event on behalf of another server.
@ -53,6 +62,21 @@ class _EventInternalMetadata(object):
        """
        return getattr(self, "send_on_behalf_of", None)

+    def need_to_check_redaction(self):
+        """Whether the redaction event needs to be rechecked when fetching
+        from the database.
+
+        Starting in room v3 redaction events are accepted up front, and later
+        checked to see if the redacter and redactee's domains match.
+
+        If the sender of the redaction event is allowed to redact any event
+        due to auth rules, then this will always return false.
+
+        Returns:
+            bool
+        """
+        return getattr(self, "recheck_redaction", False)
+

 def _event_dict_property(key):
    # We want to be able to use hasattr with the event dict properties.
@ -179,6 +203,8 @@ class EventBase(object):


 class FrozenEvent(EventBase):
+    format_version = EventFormatVersions.V1  # All events of this type are V1
+
    def __init__(self, event_dict, internal_metadata_dict={}, rejected_reason=None):
        event_dict = dict(event_dict)

@ -213,16 +239,6 @@ class FrozenEvent(EventBase):
            rejected_reason=rejected_reason,
        )

-    @staticmethod
-    def from_event(event):
-        e = FrozenEvent(
-            event.get_pdu_json()
-        )
-
-        e.internal_metadata = event.internal_metadata
-
-        return e
-
    def __str__(self):
        return self.__repr__()

@ -232,3 +248,127 @@ class FrozenEvent(EventBase):
            self.get("type", None),
            self.get("state_key", None),
        )
+
+
+class FrozenEventV2(EventBase):
+    format_version = EventFormatVersions.V2  # All events of this type are V2
+
+    def __init__(self, event_dict, internal_metadata_dict={}, rejected_reason=None):
+        event_dict = dict(event_dict)
+
+        # Signatures is a dict of dicts, and this is faster than doing a
+        # copy.deepcopy
+        signatures = {
+            name: {sig_id: sig for sig_id, sig in sigs.items()}
+            for name, sigs in event_dict.pop("signatures", {}).items()
+        }
+
+        assert "event_id" not in event_dict
+
+        unsigned = dict(event_dict.pop("unsigned", {}))
+
+        # We intern these strings because they turn up a lot (especially when
+        # caching).
+        event_dict = intern_dict(event_dict)
+
+        if USE_FROZEN_DICTS:
+            frozen_dict = freeze(event_dict)
+        else:
+            frozen_dict = event_dict
+
+        self._event_id = None
+        self.type = event_dict["type"]
+        if "state_key" in event_dict:
+            self.state_key = event_dict["state_key"]
+
+        super(FrozenEventV2, self).__init__(
+            frozen_dict,
+            signatures=signatures,
+            unsigned=unsigned,
+            internal_metadata_dict=internal_metadata_dict,
+            rejected_reason=rejected_reason,
+        )
+
+    @property
+    def event_id(self):
+        # We have to import this here as otherwise we get an import loop which
+        # is hard to break.
+        from synapse.crypto.event_signing import compute_event_reference_hash
+
+        if self._event_id:
+            return self._event_id
+        self._event_id = "$" + encode_base64(compute_event_reference_hash(self)[1])
+        return self._event_id
+
+    def prev_event_ids(self):
+        """Returns the list of prev event IDs. The order matches the order
+        specified in the event, though there is no meaning to it.
+
+        Returns:
+            list[str]: The list of event IDs of this event's prev_events
+        """
+        return self.prev_events
+
+    def auth_event_ids(self):
+        """Returns the list of auth event IDs. The order matches the order
+        specified in the event, though there is no meaning to it.
+
+        Returns:
+            list[str]: The list of event IDs of this event's auth_events
+        """
+        return self.auth_events
+
+    def __str__(self):
+        return self.__repr__()
+
+    def __repr__(self):
+        return "<FrozenEventV2 event_id='%s', type='%s', state_key='%s'>" % (
+            self.event_id,
+            self.get("type", None),
+            self.get("state_key", None),
+        )
+
+
+def room_version_to_event_format(room_version):
+    """Converts a room version string to the event format
+
+    Args:
+        room_version (str)
+
+    Returns:
+        int
+    """
+    if room_version not in KNOWN_ROOM_VERSIONS:
+        # We should have already checked version, so this should not happen
+        raise RuntimeError("Unrecognized room version %s" % (room_version,))
+
+    if room_version in (
+        RoomVersions.V1, RoomVersions.V2, RoomVersions.STATE_V2_TEST,
+    ):
+        return EventFormatVersions.V1
+    elif room_version in (RoomVersions.V3,):
+        return EventFormatVersions.V2
+    else:
+        raise RuntimeError("Unrecognized room version %s" % (room_version,))
+
+
+def event_type_from_format_version(format_version):
+    """Returns the python type to use to construct an Event object for the
+    given event format version.
+
+    Args:
+        format_version (int): The event format version
+
+    Returns:
+        type: A type that can be initialized as per the initializer of
+        `FrozenEvent`
+    """
+
+    if format_version == EventFormatVersions.V1:
+        return FrozenEvent
+    elif format_version == EventFormatVersions.V2:
+        return FrozenEventV2
+    else:
+        raise Exception(
+            "No event format %r" % (format_version,)
+        )
--- a/synapse/events/builder.py
+++ b/synapse/events/builder.py
@ -13,63 +13,270 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.

-import copy
+import attr

+from twisted.internet import defer
+
+from synapse.api.constants import (
+    KNOWN_EVENT_FORMAT_VERSIONS,
+    KNOWN_ROOM_VERSIONS,
+    MAX_DEPTH,
+    EventFormatVersions,
+)
+from synapse.crypto.event_signing import add_hashes_and_signatures
 from synapse.types import EventID
 from synapse.util.stringutils import random_string

-from . import EventBase, FrozenEvent, _event_dict_property
+from . import (
+    _EventInternalMetadata,
+    event_type_from_format_version,
+    room_version_to_event_format,
+)


-class EventBuilder(EventBase):
-    def __init__(self, key_values={}, internal_metadata_dict={}):
-        signatures = copy.deepcopy(key_values.pop("signatures", {}))
-        unsigned = copy.deepcopy(key_values.pop("unsigned", {}))
+@attr.s(slots=True, cmp=False, frozen=True)
+class EventBuilder(object):
+    """A format independent event builder used to build up the event content
+    before signing the event.

-        super(EventBuilder, self).__init__(
-            key_values,
-            signatures=signatures,
-            unsigned=unsigned,
-            internal_metadata_dict=internal_metadata_dict,
+    (Note that while objects of this class are frozen, the
+    content/unsigned/internal_metadata fields are still mutable)
+
+    Attributes:
+        format_version (int): Event format version
+        room_id (str)
+        type (str)
+        sender (str)
+        content (dict)
+        unsigned (dict)
+        internal_metadata (_EventInternalMetadata)
+
+        _state (StateHandler)
+        _auth (synapse.api.Auth)
+        _store (DataStore)
+        _clock (Clock)
+        _hostname (str): The hostname of the server creating the event
+        _signing_key: The signing key to use to sign the event as the server
+    """
+
+    _state = attr.ib()
+    _auth = attr.ib()
+    _store = attr.ib()
+    _clock = attr.ib()
+    _hostname = attr.ib()
+    _signing_key = attr.ib()
+
+    format_version = attr.ib()
+
+    room_id = attr.ib()
+    type = attr.ib()
+    sender = attr.ib()
+
+    content = attr.ib(default=attr.Factory(dict))
+    unsigned = attr.ib(default=attr.Factory(dict))
+
+    # These only exist on a subset of events, so they raise AttributeError if
+    # someone tries to get them when they don't exist.
+    _state_key = attr.ib(default=None)
+    _redacts = attr.ib(default=None)
+
+    internal_metadata = attr.ib(default=attr.Factory(lambda: _EventInternalMetadata({})))
+
+    @property
+    def state_key(self):
+        if self._state_key is not None:
+            return self._state_key
+
+        raise AttributeError("state_key")
+
+    def is_state(self):
+        return self._state_key is not None
+
+    @defer.inlineCallbacks
+    def build(self, prev_event_ids):
+        """Transform into a fully signed and hashed event
+
+        Args:
+            prev_event_ids (list[str]): The event IDs to use as the prev events
+
+        Returns:
+            Deferred[FrozenEvent]
+        """
+
+        state_ids = yield self._state.get_current_state_ids(
+            self.room_id, prev_event_ids,
+        )
+        auth_ids = yield self._auth.compute_auth_events(
+            self, state_ids,
        )

-    event_id = _event_dict_property("event_id")
-    state_key = _event_dict_property("state_key")
-    type = _event_dict_property("type")
+        if self.format_version == EventFormatVersions.V1:
+            auth_events = yield self._store.add_event_hashes(auth_ids)
+            prev_events = yield self._store.add_event_hashes(prev_event_ids)
+        else:
+            auth_events = auth_ids
+            prev_events = prev_event_ids

-    def build(self):
-        return FrozenEvent.from_event(self)
+        old_depth = yield self._store.get_max_depth_of(
+            prev_event_ids,
+        )
+        depth = old_depth + 1
+
+        # we cap depth of generated events, to ensure that they are not
+        # rejected by other servers (and so that they can be persisted in
+        # the db)
+        depth = min(depth, MAX_DEPTH)
+
+        event_dict = {
+            "auth_events": auth_events,
+            "prev_events": prev_events,
+            "type": self.type,
+            "room_id": self.room_id,
+            "sender": self.sender,
+            "content": self.content,
+            "unsigned": self.unsigned,
+            "depth": depth,
+            "prev_state": [],
+        }
+
+        if self.is_state():
+            event_dict["state_key"] = self._state_key
+
+        if self._redacts is not None:
+            event_dict["redacts"] = self._redacts
+
+        defer.returnValue(
+            create_local_event_from_event_dict(
+                clock=self._clock,
+                hostname=self._hostname,
+                signing_key=self._signing_key,
+                format_version=self.format_version,
+                event_dict=event_dict,
+                internal_metadata_dict=self.internal_metadata.get_dict(),
+            )
+        )


 class EventBuilderFactory(object):
-    def __init__(self, clock, hostname):
-        self.clock = clock
-        self.hostname = hostname
+    def __init__(self, hs):
+        self.clock = hs.get_clock()
+        self.hostname = hs.hostname
+        self.signing_key = hs.config.signing_key[0]

-        self.event_id_count = 0
+        self.store = hs.get_datastore()
+        self.state = hs.get_state_handler()
+        self.auth = hs.get_auth()

-    def create_event_id(self):
-        i = str(self.event_id_count)
-        self.event_id_count += 1
+    def new(self, room_version, key_values):
+        """Generate an event builder appropriate for the given room version

-        local_part = str(int(self.clock.time())) + i + random_string(5)
+        Args:
+            room_version (str): Version of the room that we're creating an
+                event builder for
+            key_values (dict): Fields used as the basis of the new event

-        e_id = EventID(local_part, self.hostname)
+        Returns:
+            EventBuilder
+        """

-        return e_id.to_string()
+        # There's currently only the one event version defined
+        if room_version not in KNOWN_ROOM_VERSIONS:
+            raise Exception(
+                "No event format defined for version %r" % (room_version,)
+            )

-    def new(self, key_values={}):
-        key_values["event_id"] = self.create_event_id()
+        return EventBuilder(
+            store=self.store,
+            state=self.state,
+            auth=self.auth,
+            clock=self.clock,
+            hostname=self.hostname,
+            signing_key=self.signing_key,
+            format_version=room_version_to_event_format(room_version),
+            type=key_values["type"],
+            state_key=key_values.get("state_key"),
+            room_id=key_values["room_id"],
+            sender=key_values["sender"],
+            content=key_values.get("content", {}),
+            unsigned=key_values.get("unsigned", {}),
+            redacts=key_values.get("redacts", None),
+        )

-        time_now = int(self.clock.time_msec())

-        key_values.setdefault("origin", self.hostname)
-        key_values.setdefault("origin_server_ts", time_now)
+def create_local_event_from_event_dict(clock, hostname, signing_key,
+                                       format_version, event_dict,
+                                       internal_metadata_dict=None):
+    """Takes a fully formed event dict, ensuring that fields like `origin`
+    and `origin_server_ts` have correct values for a locally produced event,
+    then signs and hashes it.

-        key_values.setdefault("unsigned", {})
-        age = key_values["unsigned"].pop("age", 0)
-        key_values["unsigned"].setdefault("age_ts", time_now - age)
+    Args:
+        clock (Clock)
+        hostname (str)
+        signing_key
+        format_version (int)
+        event_dict (dict)
+        internal_metadata_dict (dict|None)

-        key_values["signatures"] = {}
+    Returns:
+        FrozenEvent
+    """

-        return EventBuilder(key_values=key_values,)
+    # There's currently only the one event version defined
+    if format_version not in KNOWN_EVENT_FORMAT_VERSIONS:
+        raise Exception(
+            "No event format defined for version %r" % (format_version,)
+        )
+
+    if internal_metadata_dict is None:
+        internal_metadata_dict = {}
+
+    time_now = int(clock.time_msec())
+
+    if format_version == EventFormatVersions.V1:
+        event_dict["event_id"] = _create_event_id(clock, hostname)
+
+    event_dict["origin"] = hostname
+    event_dict["origin_server_ts"] = time_now
+
+    event_dict.setdefault("unsigned", {})
+    age = event_dict["unsigned"].pop("age", 0)
+    event_dict["unsigned"].setdefault("age_ts", time_now - age)
+
+    event_dict.setdefault("signatures", {})
+
+    add_hashes_and_signatures(
+        event_dict,
+        hostname,
+        signing_key,
+    )
+    return event_type_from_format_version(format_version)(
+        event_dict, internal_metadata_dict=internal_metadata_dict,
+    )
+
+
+# A counter used when generating new event IDs
+_event_id_counter = 0
+
+
+def _create_event_id(clock, hostname):
+    """Create a new event ID
+
+    Args:
+        clock (Clock)
+        hostname (str): The server name for the event ID
+
+    Returns:
+        str
+    """
+
+    global _event_id_counter
+
+    i = str(_event_id_counter)
+    _event_id_counter += 1
+
+    local_part = str(int(clock.time())) + i + random_string(5)
+
+    e_id = EventID(local_part, hostname)
+
+    return e_id.to_string()
--- a/synapse/events/utils.py
+++ b/synapse/events/utils.py
@ -38,8 +38,31 @@ def prune_event(event):
    This is used when we "redact" an event. We want to remove all fields that
    the user has specified, but we do want to keep necessary information like
    type, state_key etc.
+
+    Args:
+        event (FrozenEvent)
+
+    Returns:
+        FrozenEvent
+    """
+    pruned_event_dict = prune_event_dict(event.get_dict())
+
+    from . import event_type_from_format_version
+    return event_type_from_format_version(event.format_version)(
+        pruned_event_dict, event.internal_metadata.get_dict()
+    )
+
+
+def prune_event_dict(event_dict):
+    """Redacts the event_dict in the same way as `prune_event`, except it
+    operates on dicts rather than event objects
+
+    Args:
+        event_dict (dict)
+
+    Returns:
+        dict: A copy of the pruned event dict
    """
-    event_type = event.type

    allowed_keys = [
        "event_id",
@ -59,13 +82,13 @@ def prune_event(event):
        "membership",
    ]

-    event_dict = event.get_dict()
+    event_type = event_dict["type"]

    new_content = {}

    def add_fields(*fields):
        for field in fields:
-            if field in event.content:
+            if field in event_dict["content"]:
                new_content[field] = event_dict["content"][field]

    if event_type == EventTypes.Member:
@ -98,17 +121,17 @@ def prune_event(event):

    allowed_fields["content"] = new_content

-    allowed_fields["unsigned"] = {}
+    unsigned = {}
+    allowed_fields["unsigned"] = unsigned

-    if "age_ts" in event.unsigned:
-        allowed_fields["unsigned"]["age_ts"] = event.unsigned["age_ts"]
-    if "replaces_state" in event.unsigned:
-        allowed_fields["unsigned"]["replaces_state"] = event.unsigned["replaces_state"]
+    event_unsigned = event_dict.get("unsigned", {})

-    return type(event)(
-        allowed_fields,
-        internal_metadata_dict=event.internal_metadata.get_dict()
-    )
+    if "age_ts" in event_unsigned:
+        unsigned["age_ts"] = event_unsigned["age_ts"]
+    if "replaces_state" in event_unsigned:
+        unsigned["replaces_state"] = event_unsigned["replaces_state"]
+
+    return allowed_fields


 def _copy_field(src, dst, field):
@ -244,6 +267,7 @@ def serialize_event(e, time_now_ms, as_client_event=True,
    Returns:
        dict
    """
+
    # FIXME(erikj): To handle the case of presence events and the like
    if not isinstance(e, EventBase):
        return e
@ -253,6 +277,8 @@ def serialize_event(e, time_now_ms, as_client_event=True,
    # Should this strip out None's?
    d = {k: v for k, v in e.get_dict().items()}

+    d["event_id"] = e.event_id
+
    if "age_ts" in d["unsigned"]:
        d["unsigned"]["age"] = time_now_ms - d["unsigned"]["age_ts"]
        del d["unsigned"]["age_ts"]
--- a/synapse/events/validator.py
+++ b/synapse/events/validator.py
@ -15,23 +15,29 @@

 from six import string_types

-from synapse.api.constants import EventTypes, Membership
+from synapse.api.constants import EventFormatVersions, EventTypes, Membership
 from synapse.api.errors import SynapseError
 from synapse.types import EventID, RoomID, UserID


 class EventValidator(object):
+    def validate_new(self, event):
+        """Validates the event has roughly the right format

-    def validate(self, event):
-        EventID.from_string(event.event_id)
-        RoomID.from_string(event.room_id)
+        Args:
+            event (FrozenEvent)
+        """
+        self.validate_builder(event)
+
+        if event.format_version == EventFormatVersions.V1:
+            EventID.from_string(event.event_id)

        required = [
-            # "auth_events",
+            "auth_events",
            "content",
-            # "hashes",
+            "hashes",
            "origin",
-            # "prev_events",
+            "prev_events",
            "sender",
            "type",
        ]
@ -41,8 +47,25 @@ class EventValidator(object):
                raise SynapseError(400, "Event does not have key %s" % (k,))

        # Check that the following keys have string values
-        strings = [
+        event_strings = [
            "origin",
+        ]
+
+        for s in event_strings:
+            if not isinstance(getattr(event, s), string_types):
+                raise SynapseError(400, "'%s' not a string type" % (s,))
+
+    def validate_builder(self, event):
+        """Validates that the builder/event has roughly the right format. Only
+        checks values that we expect a proto event to have, rather than all the
+        fields an event would have
+
+        Args:
+            event (EventBuilder|FrozenEvent)
+        """
+
+        strings = [
+            "room_id",
            "sender",
            "type",
        ]
@ -54,22 +77,7 @@ class EventValidator(object):
            if not isinstance(getattr(event, s), string_types):
                raise SynapseError(400, "Not '%s' a string type" % (s,))

-        if event.type == EventTypes.Member:
-            if "membership" not in event.content:
-                raise SynapseError(400, "Content has not membership key")
-
-            if event.content["membership"] not in Membership.LIST:
-                raise SynapseError(400, "Invalid membership key")
-
-        # Check that the following keys have dictionary values
-        # TODO
-
-        # Check that the following keys have the correct format for DAGs
-        # TODO
-
-    def validate_new(self, event):
-        self.validate(event)
-
+        RoomID.from_string(event.room_id)
        UserID.from_string(event.sender)

        if event.type == EventTypes.Message:
@ -86,9 +94,16 @@ class EventValidator(object):
        elif event.type == EventTypes.Name:
            self._ensure_strings(event.content, ["name"])

+        elif event.type == EventTypes.Member:
+            if "membership" not in event.content:
+                raise SynapseError(400, "Content has not membership key")
+
+            if event.content["membership"] not in Membership.LIST:
+                raise SynapseError(400, "Invalid membership key")
+
    def _ensure_strings(self, d, keys):
        for s in keys:
            if s not in d:
                raise SynapseError(400, "'%s' not in content" % (s,))
            if not isinstance(d[s], string_types):
-                raise SynapseError(400, "Not '%s' a string type" % (s,))
+                raise SynapseError(400, "'%s' not a string type" % (s,))
--- a/synapse/federation/federation_base.py
+++ b/synapse/federation/federation_base.py
@ -20,10 +20,10 @@ import six
 from twisted.internet import defer
 from twisted.internet.defer import DeferredList

-from synapse.api.constants import MAX_DEPTH, EventTypes, Membership
+from synapse.api.constants import MAX_DEPTH, EventTypes, Membership, RoomVersions
 from synapse.api.errors import Codes, SynapseError
 from synapse.crypto.event_signing import check_event_content_hash
-from synapse.events import FrozenEvent
+from synapse.events import event_type_from_format_version
 from synapse.events.utils import prune_event
 from synapse.http.servlet import assert_params_in_dict
 from synapse.types import get_domain_from_id
@ -43,8 +43,8 @@ class FederationBase(object):
        self._clock = hs.get_clock()

    @defer.inlineCallbacks
-    def _check_sigs_and_hash_and_fetch(self, origin, pdus, outlier=False,
-                                       include_none=False):
+    def _check_sigs_and_hash_and_fetch(self, origin, pdus, room_version,
+                                       outlier=False, include_none=False):
        """Takes a list of PDUs and checks the signatures and hashs of each
        one. If a PDU fails its signature check then we check if we have it in
        the database and if not then request if from the originating server of
@ -56,13 +56,17 @@ class FederationBase(object):
        a new list.

        Args:
+            origin (str)
            pdu (list)
-            outlier (bool)
+            room_version (str)
+            outlier (bool): Whether the events are outliers or not
+            include_none (str): Whether to include None in the returned list
+                for events that have failed their checks

        Returns:
            Deferred : A list of PDUs that have valid signatures and hashes.
        """
-        deferreds = self._check_sigs_and_hashes(pdus)
+        deferreds = self._check_sigs_and_hashes(room_version, pdus)

        @defer.inlineCallbacks
        def handle_check_result(pdu, deferred):
@ -84,6 +88,7 @@ class FederationBase(object):
                    res = yield self.get_pdu(
                        destinations=[pdu.origin],
                        event_id=pdu.event_id,
+                        room_version=room_version,
                        outlier=outlier,
                        timeout=10000,
                    )
@ -116,16 +121,17 @@ class FederationBase(object):
        else:
            defer.returnValue([p for p in valid_pdus if p])

-    def _check_sigs_and_hash(self, pdu):
+    def _check_sigs_and_hash(self, room_version, pdu):
        return logcontext.make_deferred_yieldable(
-            self._check_sigs_and_hashes([pdu])[0],
+            self._check_sigs_and_hashes(room_version, [pdu])[0],
        )

-    def _check_sigs_and_hashes(self, pdus):
+    def _check_sigs_and_hashes(self, room_version, pdus):
        """Checks that each of the received events is correctly signed by the
        sending server.

        Args:
+            room_version (str): The room version of the PDUs
            pdus (list[FrozenEvent]): the events to be checked

        Returns:
@ -136,7 +142,7 @@ class FederationBase(object):
              * throws a SynapseError if the signature check failed.
            The deferreds run their callbacks in the sentinel logcontext.
        """
-        deferreds = _check_sigs_on_pdus(self.keyring, pdus)
+        deferreds = _check_sigs_on_pdus(self.keyring, room_version, pdus)

        ctx = logcontext.LoggingContext.current_context()

@ -198,16 +204,17 @@ class FederationBase(object):


 class PduToCheckSig(namedtuple("PduToCheckSig", [
-    "pdu", "redacted_pdu_json", "event_id_domain", "sender_domain", "deferreds",
+    "pdu", "redacted_pdu_json", "sender_domain", "deferreds",
 ])):
    pass


-def _check_sigs_on_pdus(keyring, pdus):
+def _check_sigs_on_pdus(keyring, room_version, pdus):
    """Check that the given events are correctly signed

    Args:
        keyring (synapse.crypto.Keyring): keyring object to do the checks
+        room_version (str): the room version of the PDUs
        pdus (Collection[EventBase]): the events to be checked

    Returns:
@ -220,9 +227,7 @@ def _check_sigs_on_pdus(keyring, pdus):

    # we want to check that the event is signed by:
    #
-    # (a) the server which created the event_id
-    #
-    # (b) the sender's server.
+    # (a) the sender's server
    #
    #     - except in the case of invites created from a 3pid invite, which are exempt
    #     from this check, because the sender has to match that of the original 3pid
@ -236,34 +241,26 @@ def _check_sigs_on_pdus(keyring, pdus):
    #     and signatures are *supposed* to be valid whether or not an event has been
    #     redacted. But this isn't the worst of the ways that 3pid invites are broken.
    #
+    # (b) for V1 and V2 rooms, the server which created the event_id
+    #
    # let's start by getting the domain for each pdu, and flattening the event back
    # to JSON.
+
    pdus_to_check = [
        PduToCheckSig(
            pdu=p,
            redacted_pdu_json=prune_event(p).get_pdu_json(),
-            event_id_domain=get_domain_from_id(p.event_id),
            sender_domain=get_domain_from_id(p.sender),
            deferreds=[],
        )
        for p in pdus
    ]

-    # first make sure that the event is signed by the event_id's domain
-    deferreds = keyring.verify_json_objects_for_server([
-        (p.event_id_domain, p.redacted_pdu_json)
-        for p in pdus_to_check
-    ])
-
-    for p, d in zip(pdus_to_check, deferreds):
-        p.deferreds.append(d)
-
-    # now let's look for events where the sender's domain is different to the
-    # event id's domain (normally only the case for joins/leaves), and add additional
-    # checks.
+    # First we check that the sender event is signed by the sender's domain
+    # (except if its a 3pid invite, in which case it may be sent by any server)
    pdus_to_check_sender = [
        p for p in pdus_to_check
-        if p.sender_domain != p.event_id_domain and not _is_invite_via_3pid(p.pdu)
+        if not _is_invite_via_3pid(p.pdu)
    ]

    more_deferreds = keyring.verify_json_objects_for_server([
@ -274,19 +271,43 @@ def _check_sigs_on_pdus(keyring, pdus):
    for p, d in zip(pdus_to_check_sender, more_deferreds):
        p.deferreds.append(d)

+    # now let's look for events where the sender's domain is different to the
+    # event id's domain (normally only the case for joins/leaves), and add additional
+    # checks. Only do this if the room version has a concept of event ID domain
+    if room_version in (
+        RoomVersions.V1, RoomVersions.V2, RoomVersions.STATE_V2_TEST,
+    ):
+        pdus_to_check_event_id = [
+            p for p in pdus_to_check
+            if p.sender_domain != get_domain_from_id(p.pdu.event_id)
+        ]
+
+        more_deferreds = keyring.verify_json_objects_for_server([
+            (get_domain_from_id(p.pdu.event_id), p.redacted_pdu_json)
+            for p in pdus_to_check_event_id
+        ])
+
+        for p, d in zip(pdus_to_check_event_id, more_deferreds):
+            p.deferreds.append(d)
+    elif room_version in (RoomVersions.V3,):
+        pass  # No further checks needed, as event IDs are hashes here
+    else:
+        raise RuntimeError("Unrecognized room version %s" % (room_version,))
+
    # replace lists of deferreds with single Deferreds
    return [_flatten_deferred_list(p.deferreds) for p in pdus_to_check]


 def _flatten_deferred_list(deferreds):
-    """Given a list of one or more deferreds, either return the single deferred, or
-    combine into a DeferredList.
+    """Given a list of deferreds, either return the single deferred,
+    combine into a DeferredList, or return an already resolved deferred.
    """
    if len(deferreds) > 1:
        return DeferredList(deferreds, fireOnOneErrback=True, consumeErrors=True)
-    else:
-        assert len(deferreds) == 1
+    elif len(deferreds) == 1:
        return deferreds[0]
+    else:
+        return defer.succeed(None)


 def _is_invite_via_3pid(event):
@ -297,11 +318,12 @@ def _is_invite_via_3pid(event):
    )


-def event_from_pdu_json(pdu_json, outlier=False):
+def event_from_pdu_json(pdu_json, event_format_version, outlier=False):
    """Construct a FrozenEvent from an event json received over federation

    Args:
        pdu_json (object): pdu as received over federation
+        event_format_version (int): The event format version
        outlier (bool): True to mark this event as an outlier

    Returns:
@ -313,7 +335,7 @@ def event_from_pdu_json(pdu_json, outlier=False):
    """
    # we could probably enforce a bunch of other fields here (room_id, sender,
    # origin, etc etc)
-    assert_params_in_dict(pdu_json, ('event_id', 'type', 'depth'))
+    assert_params_in_dict(pdu_json, ('type', 'depth'))

    depth = pdu_json['depth']
    if not isinstance(depth, six.integer_types):
@ -325,8 +347,8 @@ def event_from_pdu_json(pdu_json, outlier=False):
    elif depth > MAX_DEPTH:
        raise SynapseError(400, "Depth too large", Codes.BAD_JSON)

-    event = FrozenEvent(
-        pdu_json
+    event = event_type_from_format_version(event_format_version)(
+        pdu_json,
    )

    event.internal_metadata.outlier = outlier
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@ -25,14 +25,19 @@ from prometheus_client import Counter

 from twisted.internet import defer

-from synapse.api.constants import KNOWN_ROOM_VERSIONS, EventTypes, Membership
+from synapse.api.constants import (
+    KNOWN_ROOM_VERSIONS,
+    EventTypes,
+    Membership,
+    RoomVersions,
+)
 from synapse.api.errors import (
    CodeMessageException,
    FederationDeniedError,
    HttpResponseException,
    SynapseError,
 )
-from synapse.events import builder
+from synapse.events import builder, room_version_to_event_format
 from synapse.federation.federation_base import FederationBase, event_from_pdu_json
 from synapse.util import logcontext, unwrapFirstError
 from synapse.util.caches.expiringcache import ExpiringCache
@ -66,6 +71,9 @@ class FederationClient(FederationBase):
        self.state = hs.get_state_handler()
        self.transport_layer = hs.get_federation_transport_client()

+        self.hostname = hs.hostname
+        self.signing_key = hs.config.signing_key[0]
+
        self._get_pdu_cache = ExpiringCache(
            cache_name="get_pdu_cache",
            clock=self._clock,
@ -162,13 +170,13 @@ class FederationClient(FederationBase):

    @defer.inlineCallbacks
    @log_function
-    def backfill(self, dest, context, limit, extremities):
+    def backfill(self, dest, room_id, limit, extremities):
        """Requests some more historic PDUs for the given context from the
        given destination server.

        Args:
            dest (str): The remote home server to ask.
-            context (str): The context to backfill.
+            room_id (str): The room_id to backfill.
            limit (int): The maximum number of PDUs to return.
            extremities (list): List of PDU id and origins of the first pdus
                we have seen from the context
@ -183,18 +191,21 @@ class FederationClient(FederationBase):
            return

        transaction_data = yield self.transport_layer.backfill(
-            dest, context, extremities, limit)
+            dest, room_id, extremities, limit)

        logger.debug("backfill transaction_data=%s", repr(transaction_data))

+        room_version = yield self.store.get_room_version(room_id)
+        format_ver = room_version_to_event_format(room_version)
+
        pdus = [
-            event_from_pdu_json(p, outlier=False)
+            event_from_pdu_json(p, format_ver, outlier=False)
            for p in transaction_data["pdus"]
        ]

        # FIXME: We should handle signature failures more gracefully.
        pdus[:] = yield logcontext.make_deferred_yieldable(defer.gatherResults(
-            self._check_sigs_and_hashes(pdus),
+            self._check_sigs_and_hashes(room_version, pdus),
            consumeErrors=True,
        ).addErrback(unwrapFirstError))

@ -202,7 +213,8 @@ class FederationClient(FederationBase):

    @defer.inlineCallbacks
    @log_function
-    def get_pdu(self, destinations, event_id, outlier=False, timeout=None):
+    def get_pdu(self, destinations, event_id, room_version, outlier=False,
+                timeout=None):
        """Requests the PDU with given origin and ID from the remote home
        servers.

@ -212,6 +224,7 @@ class FederationClient(FederationBase):
        Args:
            destinations (list): Which home servers to query
            event_id (str): event to fetch
+            room_version (str): version of the room
            outlier (bool): Indicates whether the PDU is an `outlier`, i.e. if
                it's from an arbitary point in the context as opposed to part
                of the current block of PDUs. Defaults to `False`
@ -230,6 +243,8 @@ class FederationClient(FederationBase):

        pdu_attempts = self.pdu_destination_tried.setdefault(event_id, {})

+        format_ver = room_version_to_event_format(room_version)
+
        signed_pdu = None
        for destination in destinations:
            now = self._clock.time_msec()
@ -245,7 +260,7 @@ class FederationClient(FederationBase):
                logger.debug("transaction_data %r", transaction_data)

                pdu_list = [
-                    event_from_pdu_json(p, outlier=outlier)
+                    event_from_pdu_json(p, format_ver, outlier=outlier)
                    for p in transaction_data["pdus"]
                ]

@ -253,7 +268,7 @@ class FederationClient(FederationBase):
                    pdu = pdu_list[0]

                    # Check signatures are correct.
-                    signed_pdu = yield self._check_sigs_and_hash(pdu)
+                    signed_pdu = yield self._check_sigs_and_hash(room_version, pdu)

                    break

@ -339,12 +354,16 @@ class FederationClient(FederationBase):
            destination, room_id, event_id=event_id,
        )

+        room_version = yield self.store.get_room_version(room_id)
+        format_ver = room_version_to_event_format(room_version)
+
        pdus = [
-            event_from_pdu_json(p, outlier=True) for p in result["pdus"]
+            event_from_pdu_json(p, format_ver, outlier=True)
+            for p in result["pdus"]
        ]

        auth_chain = [
-            event_from_pdu_json(p, outlier=True)
+            event_from_pdu_json(p, format_ver, outlier=True)
            for p in result.get("auth_chain", [])
        ]

@ -355,7 +374,8 @@ class FederationClient(FederationBase):
        signed_pdus = yield self._check_sigs_and_hash_and_fetch(
            destination,
            [p for p in pdus if p.event_id not in seen_events],
-            outlier=True
+            outlier=True,
+            room_version=room_version,
        )
        signed_pdus.extend(
            seen_events[p.event_id] for p in pdus if p.event_id in seen_events
@ -364,7 +384,8 @@ class FederationClient(FederationBase):
        signed_auth = yield self._check_sigs_and_hash_and_fetch(
            destination,
            [p for p in auth_chain if p.event_id not in seen_events],
-            outlier=True
+            outlier=True,
+            room_version=room_version,
        )
        signed_auth.extend(
            seen_events[p.event_id] for p in auth_chain if p.event_id in seen_events
@ -411,6 +432,8 @@ class FederationClient(FederationBase):
            random.shuffle(srvs)
            return srvs

+        room_version = yield self.store.get_room_version(room_id)
+
        batch_size = 20
        missing_events = list(missing_events)
        for i in range(0, len(missing_events), batch_size):
@ -421,6 +444,7 @@ class FederationClient(FederationBase):
                    self.get_pdu,
                    destinations=random_server_list(),
                    event_id=e_id,
+                    room_version=room_version,
                )
                for e_id in batch
            ]
@ -445,13 +469,17 @@ class FederationClient(FederationBase):
            destination, room_id, event_id,
        )

+        room_version = yield self.store.get_room_version(room_id)
+        format_ver = room_version_to_event_format(room_version)
+
        auth_chain = [
-            event_from_pdu_json(p, outlier=True)
+            event_from_pdu_json(p, format_ver, outlier=True)
            for p in res["auth_chain"]
        ]

        signed_auth = yield self._check_sigs_and_hash_and_fetch(
-            destination, auth_chain, outlier=True
+            destination, auth_chain,
+            outlier=True, room_version=room_version,
        )

        signed_auth.sort(key=lambda e: e.depth)
@ -522,6 +550,8 @@ class FederationClient(FederationBase):
        Does so by asking one of the already participating servers to create an
        event with proper context.

+        Returns a fully signed and hashed event.
+
        Note that this does not append any events to any graphs.

        Args:
@ -536,8 +566,10 @@ class FederationClient(FederationBase):
            params (dict[str, str|Iterable[str]]): Query parameters to include in the
                request.
        Return:
-            Deferred: resolves to a tuple of (origin (str), event (object))
-            where origin is the remote homeserver which generated the event.
+            Deferred[tuple[str, FrozenEvent, int]]: resolves to a tuple of
+            `(origin, event, event_format)` where origin is the remote
+            homeserver which generated the event, and event_format is one of
+            `synapse.api.constants.EventFormatVersions`.

            Fails with a ``SynapseError`` if the chosen remote server
            returns a 300/400 code.
@ -557,6 +589,11 @@ class FederationClient(FederationBase):
                destination, room_id, user_id, membership, params,
            )

+            # Note: If not supplied, the room version may be either v1 or v2,
+            # however either way the event format version will be v1.
+            room_version = ret.get("room_version", RoomVersions.V1)
+            event_format = room_version_to_event_format(room_version)
+
            pdu_dict = ret.get("event", None)
            if not isinstance(pdu_dict, dict):
                raise InvalidResponseError("Bad 'event' field in response")
@ -571,17 +608,20 @@ class FederationClient(FederationBase):
            if "prev_state" not in pdu_dict:
                pdu_dict["prev_state"] = []

-            ev = builder.EventBuilder(pdu_dict)
+            ev = builder.create_local_event_from_event_dict(
+                self._clock, self.hostname, self.signing_key,
+                format_version=event_format, event_dict=pdu_dict,
+            )

            defer.returnValue(
-                (destination, ev)
+                (destination, ev, event_format)
            )

        return self._try_destination_list(
            "make_" + membership, destinations, send_request,
        )

-    def send_join(self, destinations, pdu):
+    def send_join(self, destinations, pdu, event_format_version):
        """Sends a join event to one of a list of homeservers.

        Doing so will cause the remote server to add the event to the graph,
@ -591,6 +631,7 @@ class FederationClient(FederationBase):
            destinations (str): Candidate homeservers which are probably
                participating in the room.
            pdu (BaseEvent): event to be sent
+            event_format_version (int): The event format version

        Return:
            Deferred: resolves to a dict with members ``origin`` (a string
@ -636,12 +677,12 @@ class FederationClient(FederationBase):
            logger.debug("Got content: %s", content)

            state = [
-                event_from_pdu_json(p, outlier=True)
+                event_from_pdu_json(p, event_format_version, outlier=True)
                for p in content.get("state", [])
            ]

            auth_chain = [
-                event_from_pdu_json(p, outlier=True)
+                event_from_pdu_json(p, event_format_version, outlier=True)
                for p in content.get("auth_chain", [])
            ]

@ -650,9 +691,21 @@ class FederationClient(FederationBase):
                for p in itertools.chain(state, auth_chain)
            }

+            room_version = None
+            for e in state:
+                if (e.type, e.state_key) == (EventTypes.Create, ""):
+                    room_version = e.content.get("room_version", RoomVersions.V1)
+                    break
+
+            if room_version is None:
+                # If the state doesn't have a create event then the room is
+                # invalid, and it would fail auth checks anyway.
+                raise SynapseError(400, "No create event in state")
+
            valid_pdus = yield self._check_sigs_and_hash_and_fetch(
                destination, list(pdus.values()),
                outlier=True,
+                room_version=room_version,
            )

            valid_pdus_map = {
@ -690,32 +743,75 @@ class FederationClient(FederationBase):

    @defer.inlineCallbacks
    def send_invite(self, destination, room_id, event_id, pdu):
-        time_now = self._clock.time_msec()
-        try:
-            code, content = yield self.transport_layer.send_invite(
-                destination=destination,
-                room_id=room_id,
-                event_id=event_id,
-                content=pdu.get_pdu_json(time_now),
-            )
-        except HttpResponseException as e:
-            if e.code == 403:
-                raise e.to_synapse_error()
-            raise
+        room_version = yield self.store.get_room_version(room_id)
+
+        content = yield self._do_send_invite(destination, pdu, room_version)

        pdu_dict = content["event"]

        logger.debug("Got response to send_invite: %s", pdu_dict)

-        pdu = event_from_pdu_json(pdu_dict)
+        room_version = yield self.store.get_room_version(room_id)
+        format_ver = room_version_to_event_format(room_version)
+
+        pdu = event_from_pdu_json(pdu_dict, format_ver)

        # Check signatures are correct.
-        pdu = yield self._check_sigs_and_hash(pdu)
+        pdu = yield self._check_sigs_and_hash(room_version, pdu)

        # FIXME: We should handle signature failures more gracefully.

        defer.returnValue(pdu)

+    @defer.inlineCallbacks
+    def _do_send_invite(self, destination, pdu, room_version):
+        """Actually sends the invite, first trying v2 API and falling back to
+        v1 API if necessary.
+
+        Args:
+            destination (str): Target server
+            pdu (FrozenEvent)
+            room_version (str)
+
+        Returns:
+            dict: The event as a dict as returned by the remote server
+        """
+        time_now = self._clock.time_msec()
+
+        try:
+            content = yield self.transport_layer.send_invite_v2(
+                destination=destination,
+                room_id=pdu.room_id,
+                event_id=pdu.event_id,
+                content={
+                    "event": pdu.get_pdu_json(time_now),
+                    "room_version": room_version,
+                    "invite_room_state": pdu.unsigned.get("invite_room_state", []),
+                },
+            )
+            defer.returnValue(content)
+        except HttpResponseException as e:
+            if e.code in [400, 404]:
+                if room_version in (RoomVersions.V1, RoomVersions.V2):
+                    pass  # We'll fall through
+                else:
+                    raise Exception("Remote server is too old")
+            elif e.code == 403:
+                raise e.to_synapse_error()
+            else:
+                raise
+
+        # Didn't work, try v1 API.
+        # Note the v1 API returns a tuple of `(200, content)`
+
+        _, content = yield self.transport_layer.send_invite_v1(
+            destination=destination,
+            room_id=pdu.room_id,
+            event_id=pdu.event_id,
+            content=pdu.get_pdu_json(time_now),
+        )
+        defer.returnValue(content)
+
    def send_leave(self, destinations, pdu):
        """Sends a leave event to one of a list of homeservers.

@ -785,13 +881,16 @@ class FederationClient(FederationBase):
            content=send_content,
        )

+        room_version = yield self.store.get_room_version(room_id)
+        format_ver = room_version_to_event_format(room_version)
+
        auth_chain = [
-            event_from_pdu_json(e)
+            event_from_pdu_json(e, format_ver)
            for e in content["auth_chain"]
        ]

        signed_auth = yield self._check_sigs_and_hash_and_fetch(
-            destination, auth_chain, outlier=True
+            destination, auth_chain, outlier=True, room_version=room_version,
        )

        signed_auth.sort(key=lambda e: e.depth)
@ -833,13 +932,16 @@ class FederationClient(FederationBase):
                timeout=timeout,
            )

+            room_version = yield self.store.get_room_version(room_id)
+            format_ver = room_version_to_event_format(room_version)
+
            events = [
-                event_from_pdu_json(e)
+                event_from_pdu_json(e, format_ver)
                for e in content.get("events", [])
            ]

            signed_events = yield self._check_sigs_and_hash_and_fetch(
-                destination, events, outlier=False
+                destination, events, outlier=False, room_version=room_version,
            )
        except HttpResponseException as e:
            if not e.code == 400:
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@ -25,7 +25,7 @@ from twisted.internet import defer
 from twisted.internet.abstract import isIPAddress
 from twisted.python import failure

-from synapse.api.constants import EventTypes
+from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import (
    AuthError,
    FederationError,
@ -34,6 +34,7 @@ from synapse.api.errors import (
    SynapseError,
 )
 from synapse.crypto.event_signing import compute_event_signature
+from synapse.events import room_version_to_event_format
 from synapse.federation.federation_base import FederationBase, event_from_pdu_json
 from synapse.federation.persistence import TransactionActions
 from synapse.federation.units import Edu, Transaction
@ -178,14 +179,13 @@ class FederationServer(FederationBase):
                continue

            try:
-                # In future we will actually use the room version to parse the
-                # PDU into an event.
-                yield self.store.get_room_version(room_id)
+                room_version = yield self.store.get_room_version(room_id)
+                format_ver = room_version_to_event_format(room_version)
            except NotFoundError:
                logger.info("Ignoring PDU for unknown room_id: %s", room_id)
                continue

-            event = event_from_pdu_json(p)
+            event = event_from_pdu_json(p, format_ver)
            pdus_by_room.setdefault(room_id, []).append(event)

        pdu_results = {}
@ -322,7 +322,7 @@ class FederationServer(FederationBase):
            if self.hs.is_mine_id(event.event_id):
                event.signatures.update(
                    compute_event_signature(
-                        event,
+                        event.get_pdu_json(),
                        self.hs.hostname,
                        self.hs.config.signing_key[0]
                    )
@ -370,7 +370,9 @@ class FederationServer(FederationBase):

    @defer.inlineCallbacks
    def on_invite_request(self, origin, content, room_version):
-        pdu = event_from_pdu_json(content)
+        format_ver = room_version_to_event_format(room_version)
+
+        pdu = event_from_pdu_json(content, format_ver)
        origin_host, _ = parse_server_name(origin)
        yield self.check_server_matches_acl(origin_host, pdu.room_id)
        ret_pdu = yield self.handler.on_invite_request(origin, pdu)
@ -378,9 +380,12 @@ class FederationServer(FederationBase):
        defer.returnValue({"event": ret_pdu.get_pdu_json(time_now)})

    @defer.inlineCallbacks
-    def on_send_join_request(self, origin, content):
+    def on_send_join_request(self, origin, content, room_id):
        logger.debug("on_send_join_request: content: %s", content)
-        pdu = event_from_pdu_json(content)
+
+        room_version = yield self.store.get_room_version(room_id)
+        format_ver = room_version_to_event_format(room_version)
+        pdu = event_from_pdu_json(content, format_ver)

        origin_host, _ = parse_server_name(origin)
        yield self.check_server_matches_acl(origin_host, pdu.room_id)
@ -400,13 +405,22 @@ class FederationServer(FederationBase):
        origin_host, _ = parse_server_name(origin)
        yield self.check_server_matches_acl(origin_host, room_id)
        pdu = yield self.handler.on_make_leave_request(room_id, user_id)
+
+        room_version = yield self.store.get_room_version(room_id)
+
        time_now = self._clock.time_msec()
-        defer.returnValue({"event": pdu.get_pdu_json(time_now)})
+        defer.returnValue({
+            "event": pdu.get_pdu_json(time_now),
+            "room_version": room_version,
+        })

    @defer.inlineCallbacks
-    def on_send_leave_request(self, origin, content):
+    def on_send_leave_request(self, origin, content, room_id):
        logger.debug("on_send_leave_request: content: %s", content)
-        pdu = event_from_pdu_json(content)
+
+        room_version = yield self.store.get_room_version(room_id)
+        format_ver = room_version_to_event_format(room_version)
+        pdu = event_from_pdu_json(content, format_ver)

        origin_host, _ = parse_server_name(origin)
        yield self.check_server_matches_acl(origin_host, pdu.room_id)
@ -452,13 +466,16 @@ class FederationServer(FederationBase):
            origin_host, _ = parse_server_name(origin)
            yield self.check_server_matches_acl(origin_host, room_id)

+            room_version = yield self.store.get_room_version(room_id)
+            format_ver = room_version_to_event_format(room_version)
+
            auth_chain = [
-                event_from_pdu_json(e)
+                event_from_pdu_json(e, format_ver)
                for e in content["auth_chain"]
            ]

            signed_auth = yield self._check_sigs_and_hash_and_fetch(
-                origin, auth_chain, outlier=True
+                origin, auth_chain, outlier=True, room_version=room_version,
            )

            ret = yield self.handler.on_query_auth(
@ -603,16 +620,19 @@ class FederationServer(FederationBase):
        """
        # check that it's actually being sent from a valid destination to
        # workaround bug #1753 in 0.18.5 and 0.18.6
-        if origin != get_domain_from_id(pdu.event_id):
+        if origin != get_domain_from_id(pdu.sender):
            # We continue to accept join events from any server; this is
            # necessary for the federation join dance to work correctly.
            # (When we join over federation, the "helper" server is
            # responsible for sending out the join event, rather than the
-            # origin. See bug #1893).
+            # origin. See bug #1893. This is also true for some third party
+            # invites).
            if not (
                pdu.type == 'm.room.member' and
                pdu.content and
-                pdu.content.get("membership", None) == 'join'
+                pdu.content.get("membership", None) in (
+                    Membership.JOIN, Membership.INVITE,
+                )
            ):
                logger.info(
                    "Discarding PDU %s from invalid origin %s",
@ -625,9 +645,12 @@ class FederationServer(FederationBase):
                    pdu.event_id, origin
                )

+        # We've already checked that we know the room version by this point
+        room_version = yield self.store.get_room_version(pdu.room_id)
+
        # Check signature.
        try:
-            pdu = yield self._check_sigs_and_hash(pdu)
+            pdu = yield self._check_sigs_and_hash(room_version, pdu)
        except SynapseError as e:
            raise FederationError(
                "ERROR",
--- a/synapse/federation/transaction_queue.py
+++ b/synapse/federation/transaction_queue.py
@ -175,7 +175,7 @@ class TransactionQueue(object):
                def handle_event(event):
                    # Only send events for this server.
                    send_on_behalf_of = event.internal_metadata.get_send_on_behalf_of()
-                    is_mine = self.is_mine_id(event.event_id)
+                    is_mine = self.is_mine_id(event.sender)
                    if not is_mine and send_on_behalf_of is None:
                        return

--- a/synapse/federation/transport/client.py
+++ b/synapse/federation/transport/client.py
@ -21,7 +21,7 @@ from six.moves import urllib
 from twisted.internet import defer

 from synapse.api.constants import Membership
-from synapse.api.urls import FEDERATION_V1_PREFIX
+from synapse.api.urls import FEDERATION_V1_PREFIX, FEDERATION_V2_PREFIX
 from synapse.util.logutils import log_function

 logger = logging.getLogger(__name__)
@ -289,7 +289,7 @@ class TransportLayerClient(object):

    @defer.inlineCallbacks
    @log_function
-    def send_invite(self, destination, room_id, event_id, content):
+    def send_invite_v1(self, destination, room_id, event_id, content):
        path = _create_v1_path("/invite/%s/%s", room_id, event_id)

        response = yield self.client.put_json(
@ -301,6 +301,20 @@ class TransportLayerClient(object):

        defer.returnValue(response)

+    @defer.inlineCallbacks
+    @log_function
+    def send_invite_v2(self, destination, room_id, event_id, content):
+        path = _create_v2_path("/invite/%s/%s", room_id, event_id)
+
+        response = yield self.client.put_json(
+            destination=destination,
+            path=path,
+            data=content,
+            ignore_backoff=True,
+        )
+
+        defer.returnValue(response)
+
    @defer.inlineCallbacks
    @log_function
    def get_public_rooms(self, remote_server, limit, since_token,
@ -958,3 +972,24 @@ def _create_v1_path(path, *args):
        FEDERATION_V1_PREFIX
        + path % tuple(urllib.parse.quote(arg, "") for arg in args)
    )
+
+
+def _create_v2_path(path, *args):
+    """Creates a path against V2 federation API from the path template and
+    args. Ensures that all args are url encoded.
+
+    Example:
+
+        _create_v2_path("/event/%s/", event_id)
+
+    Args:
+        path (str): String template for the path
+        args: ([str]): Args to insert into path. Each arg will be url encoded
+
+    Returns:
+        str
+    """
+    return (
+        FEDERATION_V2_PREFIX
+        + path % tuple(urllib.parse.quote(arg, "") for arg in args)
+    )
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@ -469,7 +469,7 @@ class FederationSendLeaveServlet(BaseFederationServlet):

    @defer.inlineCallbacks
    def on_PUT(self, origin, content, query, room_id, event_id):
-        content = yield self.handler.on_send_leave_request(origin, content)
+        content = yield self.handler.on_send_leave_request(origin, content, room_id)
        defer.returnValue((200, content))


@ -487,7 +487,7 @@ class FederationSendJoinServlet(BaseFederationServlet):
    def on_PUT(self, origin, content, query, context, event_id):
        # TODO(paul): assert that context/event_id parsed from path actually
        #   match those given in content
-        content = yield self.handler.on_send_join_request(origin, content)
+        content = yield self.handler.on_send_join_request(origin, content, context)
        defer.returnValue((200, content))


--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@ -34,6 +34,7 @@ from synapse.api.constants import (
    EventTypes,
    Membership,
    RejectedReason,
+    RoomVersions,
 )
 from synapse.api.errors import (
    AuthError,
@ -43,10 +44,7 @@ from synapse.api.errors import (
    StoreError,
    SynapseError,
 )
-from synapse.crypto.event_signing import (
-    add_hashes_and_signatures,
-    compute_event_signature,
-)
+from synapse.crypto.event_signing import compute_event_signature
 from synapse.events.validator import EventValidator
 from synapse.replication.http.federation import (
    ReplicationCleanRoomRestServlet,
@ -58,7 +56,6 @@ from synapse.types import UserID, get_domain_from_id
 from synapse.util import logcontext, unwrapFirstError
 from synapse.util.async_helpers import Linearizer
 from synapse.util.distributor import user_joined_room
-from synapse.util.frozenutils import unfreeze
 from synapse.util.logutils import log_function
 from synapse.util.retryutils import NotRetryingDestination
 from synapse.visibility import filter_events_for_server
@ -342,6 +339,8 @@ class FederationHandler(BaseHandler):
                            room_id, event_id, p,
                        )

+                        room_version = yield self.store.get_room_version(room_id)
+
                        with logcontext.nested_logging_context(p):
                            # note that if any of the missing prevs share missing state or
                            # auth events, the requests to fetch those events are deduped
@ -355,7 +354,7 @@ class FederationHandler(BaseHandler):
                            # we want the state *after* p; get_state_for_room returns the
                            # state *before* p.
                            remote_event = yield self.federation_client.get_pdu(
-                                [origin], p, outlier=True,
+                                [origin], p, room_version, outlier=True,
                            )

                            if remote_event is None:
@ -379,7 +378,6 @@ class FederationHandler(BaseHandler):
                            for x in remote_state:
                                event_map[x.event_id] = x

-                    room_version = yield self.store.get_room_version(room_id)
                    state_map = yield resolve_events_with_store(
                        room_version, state_maps, event_map,
                        state_res_store=StateResolutionStore(self.store),
@ -655,6 +653,8 @@ class FederationHandler(BaseHandler):
        if dest == self.server_name:
            raise SynapseError(400, "Can't backfill from self.")

+        room_version = yield self.store.get_room_version(room_id)
+
        events = yield self.federation_client.backfill(
            dest,
            room_id,
@ -748,6 +748,7 @@ class FederationHandler(BaseHandler):
                            self.federation_client.get_pdu,
                            [dest],
                            event_id,
+                            room_version=room_version,
                            outlier=True,
                            timeout=10000,
                        )
@ -1060,7 +1061,7 @@ class FederationHandler(BaseHandler):
        """
        logger.debug("Joining %s to %s", joinee, room_id)

-        origin, event = yield self._make_and_verify_event(
+        origin, event, event_format_version = yield self._make_and_verify_event(
            target_hosts,
            room_id,
            joinee,
@ -1083,7 +1084,6 @@ class FederationHandler(BaseHandler):
        handled_events = set()

        try:
-            event = self._sign_event(event)
            # Try the host we successfully got a response to /make_join/
            # request first.
            try:
@ -1091,7 +1091,9 @@ class FederationHandler(BaseHandler):
                target_hosts.insert(0, origin)
            except ValueError:
                pass
-            ret = yield self.federation_client.send_join(target_hosts, event)
+            ret = yield self.federation_client.send_join(
+                target_hosts, event, event_format_version,
+            )

            origin = ret["origin"]
            state = ret["state"]
@ -1164,13 +1166,18 @@ class FederationHandler(BaseHandler):
        """
        event_content = {"membership": Membership.JOIN}

-        builder = self.event_builder_factory.new({
-            "type": EventTypes.Member,
-            "content": event_content,
-            "room_id": room_id,
-            "sender": user_id,
-            "state_key": user_id,
-        })
+        room_version = yield self.store.get_room_version(room_id)
+
+        builder = self.event_builder_factory.new(
+            room_version,
+            {
+                "type": EventTypes.Member,
+                "content": event_content,
+                "room_id": room_id,
+                "sender": user_id,
+                "state_key": user_id,
+            }
+        )

        try:
            event, context = yield self.event_creation_handler.create_new_client_event(
@ -1182,7 +1189,9 @@ class FederationHandler(BaseHandler):

        # The remote hasn't signed it yet, obviously. We'll do the full checks
        # when we get the event back in `on_send_join_request`
-        yield self.auth.check_from_context(event, context, do_sig_check=False)
+        yield self.auth.check_from_context(
+            room_version, event, context, do_sig_check=False,
+        )

        defer.returnValue(event)

@ -1287,11 +1296,11 @@ class FederationHandler(BaseHandler):
            )

        event.internal_metadata.outlier = True
-        event.internal_metadata.invite_from_remote = True
+        event.internal_metadata.out_of_band_membership = True

        event.signatures.update(
            compute_event_signature(
-                event,
+                event.get_pdu_json(),
                self.hs.hostname,
                self.hs.config.signing_key[0]
            )
@ -1304,7 +1313,7 @@ class FederationHandler(BaseHandler):

    @defer.inlineCallbacks
    def do_remotely_reject_invite(self, target_hosts, room_id, user_id):
-        origin, event = yield self._make_and_verify_event(
+        origin, event, event_format_version = yield self._make_and_verify_event(
            target_hosts,
            room_id,
            user_id,
@ -1313,7 +1322,7 @@ class FederationHandler(BaseHandler):
        # Mark as outlier as we don't have any state for this event; we're not
        # even in the room.
        event.internal_metadata.outlier = True
-        event = self._sign_event(event)
+        event.internal_metadata.out_of_band_membership = True

        # Try the host that we succesfully called /make_leave/ on first for
        # the /send_leave/ request.
@ -1336,7 +1345,7 @@ class FederationHandler(BaseHandler):
    @defer.inlineCallbacks
    def _make_and_verify_event(self, target_hosts, room_id, user_id, membership,
                               content={}, params=None):
-        origin, pdu = yield self.federation_client.make_membership_event(
+        origin, event, format_ver = yield self.federation_client.make_membership_event(
            target_hosts,
            room_id,
            user_id,
@ -1345,9 +1354,7 @@ class FederationHandler(BaseHandler):
            params=params,
        )

-        logger.debug("Got response to make_%s: %s", membership, pdu)
-
-        event = pdu
+        logger.debug("Got response to make_%s: %s", membership, event)

        # We should assert some things.
        # FIXME: Do this in a nicer way
@ -1355,28 +1362,7 @@ class FederationHandler(BaseHandler):
        assert(event.user_id == user_id)
        assert(event.state_key == user_id)
        assert(event.room_id == room_id)
-        defer.returnValue((origin, event))
-
-    def _sign_event(self, event):
-        event.internal_metadata.outlier = False
-
-        builder = self.event_builder_factory.new(
-            unfreeze(event.get_pdu_json())
-        )
-
-        builder.event_id = self.event_builder_factory.create_event_id()
-        builder.origin = self.hs.hostname
-
-        if not hasattr(event, "signatures"):
-            builder.signatures = {}
-
-        add_hashes_and_signatures(
-            builder,
-            self.hs.hostname,
-            self.hs.config.signing_key[0],
-        )
-
-        return builder.build()
+        defer.returnValue((origin, event, format_ver))

    @defer.inlineCallbacks
    @log_function
@ -1385,13 +1371,17 @@ class FederationHandler(BaseHandler):
        leave event for the room and return that. We do *not* persist or
        process it until the other server has signed it and sent it back.
        """
-        builder = self.event_builder_factory.new({
-            "type": EventTypes.Member,
-            "content": {"membership": Membership.LEAVE},
-            "room_id": room_id,
-            "sender": user_id,
-            "state_key": user_id,
-        })
+        room_version = yield self.store.get_room_version(room_id)
+        builder = self.event_builder_factory.new(
+            room_version,
+            {
+                "type": EventTypes.Member,
+                "content": {"membership": Membership.LEAVE},
+                "room_id": room_id,
+                "sender": user_id,
+                "state_key": user_id,
+            }
+        )

        event, context = yield self.event_creation_handler.create_new_client_event(
            builder=builder,
@ -1400,7 +1390,9 @@ class FederationHandler(BaseHandler):
        try:
            # The remote hasn't signed it yet, obviously. We'll do the full checks
            # when we get the event back in `on_send_leave_request`
-            yield self.auth.check_from_context(event, context, do_sig_check=False)
+            yield self.auth.check_from_context(
+                room_version, event, context, do_sig_check=False,
+            )
        except AuthError as e:
            logger.warn("Failed to create new leave %r because %s", event, e)
            raise e
@ -1659,6 +1651,13 @@ class FederationHandler(BaseHandler):
                create_event = e
                break

+        if create_event is None:
+            # If the state doesn't have a create event then the room is
+            # invalid, and it would fail auth checks anyway.
+            raise SynapseError(400, "No create event in state")
+
+        room_version = create_event.content.get("room_version", RoomVersions.V1)
+
        missing_auth_events = set()
        for e in itertools.chain(auth_events, state, [event]):
            for e_id in e.auth_event_ids():
@ -1669,6 +1668,7 @@ class FederationHandler(BaseHandler):
            m_ev = yield self.federation_client.get_pdu(
                [origin],
                e_id,
+                room_version=room_version,
                outlier=True,
                timeout=10000,
            )
@ -1687,7 +1687,7 @@ class FederationHandler(BaseHandler):
                auth_for_e[(EventTypes.Create, "")] = create_event

            try:
-                self.auth.check(e, auth_events=auth_for_e)
+                self.auth.check(room_version, e, auth_events=auth_for_e)
            except SynapseError as err:
                # we may get SynapseErrors here as well as AuthErrors. For
                # instance, there are a couple of (ancient) events in some
@ -1931,6 +1931,8 @@ class FederationHandler(BaseHandler):
        current_state = set(e.event_id for e in auth_events.values())
        different_auth = event_auth_events - current_state

+        room_version = yield self.store.get_room_version(event.room_id)
+
        if different_auth and not event.internal_metadata.is_outlier():
            # Do auth conflict res.
            logger.info("Different auth: %s", different_auth)
@ -1955,8 +1957,6 @@ class FederationHandler(BaseHandler):
                    (d.type, d.state_key): d for d in different_events if d
                })

-                room_version = yield self.store.get_room_version(event.room_id)
-
                new_state = yield self.state_handler.resolve_events(
                    room_version,
                    [list(local_view.values()), list(remote_view.values())],
@ -2056,7 +2056,7 @@ class FederationHandler(BaseHandler):
                )

        try:
-            self.auth.check(event, auth_events=auth_events)
+            self.auth.check(room_version, event, auth_events=auth_events)
        except AuthError as e:
            logger.warn("Failed auth resolution for %r because %s", event, e)
            raise e
@ -2279,18 +2279,26 @@ class FederationHandler(BaseHandler):
        }

        if (yield self.auth.check_host_in_room(room_id, self.hs.hostname)):
-            builder = self.event_builder_factory.new(event_dict)
-            EventValidator().validate_new(builder)
+            room_version = yield self.store.get_room_version(room_id)
+            builder = self.event_builder_factory.new(room_version, event_dict)
+
+            EventValidator().validate_builder(builder)
            event, context = yield self.event_creation_handler.create_new_client_event(
                builder=builder
            )

            event, context = yield self.add_display_name_to_third_party_invite(
-                event_dict, event, context
+                room_version, event_dict, event, context
            )

+            EventValidator().validate_new(event)
+
+            # We need to tell the transaction queue to send this out, even
+            # though the sender isn't a local user.
+            event.internal_metadata.send_on_behalf_of = self.hs.hostname
+
            try:
-                yield self.auth.check_from_context(event, context)
+                yield self.auth.check_from_context(room_version, event, context)
            except AuthError as e:
                logger.warn("Denying new third party invite %r because %s", event, e)
                raise e
@ -2317,23 +2325,31 @@ class FederationHandler(BaseHandler):
        Returns:
            Deferred: resolves (to None)
        """
-        builder = self.event_builder_factory.new(event_dict)
+        room_version = yield self.store.get_room_version(room_id)
+
+        # NB: event_dict has a particular specced format we might need to fudge
+        # if we change event formats too much.
+        builder = self.event_builder_factory.new(room_version, event_dict)

        event, context = yield self.event_creation_handler.create_new_client_event(
            builder=builder,
        )

        event, context = yield self.add_display_name_to_third_party_invite(
-            event_dict, event, context
+            room_version, event_dict, event, context
        )

        try:
-            self.auth.check_from_context(event, context)
+            self.auth.check_from_context(room_version, event, context)
        except AuthError as e:
            logger.warn("Denying third party invite %r because %s", event, e)
            raise e
        yield self._check_signature(event, context)

+        # We need to tell the transaction queue to send this out, even
+        # though the sender isn't a local user.
+        event.internal_metadata.send_on_behalf_of = get_domain_from_id(event.sender)
+
        # XXX we send the invite here, but send_membership_event also sends it,
        # so we end up making two requests. I think this is redundant.
        returned_invite = yield self.send_invite(origin, event)
@ -2344,7 +2360,8 @@ class FederationHandler(BaseHandler):
        yield member_handler.send_membership_event(None, event, context)

    @defer.inlineCallbacks
-    def add_display_name_to_third_party_invite(self, event_dict, event, context):
+    def add_display_name_to_third_party_invite(self, room_version, event_dict,
+                                               event, context):
        key = (
            EventTypes.ThirdPartyInvite,
            event.content["third_party_invite"]["signed"]["token"]
@ -2368,11 +2385,12 @@ class FederationHandler(BaseHandler):
            # auth checks. If we need the invite and don't have it then the
            # auth check code will explode appropriately.

-        builder = self.event_builder_factory.new(event_dict)
-        EventValidator().validate_new(builder)
+        builder = self.event_builder_factory.new(room_version, event_dict)
+        EventValidator().validate_builder(builder)
        event, context = yield self.event_creation_handler.create_new_client_event(
            builder=builder,
        )
+        EventValidator().validate_new(event)
        defer.returnValue((event, context))

    @defer.inlineCallbacks
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@ -22,7 +22,7 @@ from canonicaljson import encode_canonical_json, json
 from twisted.internet import defer
 from twisted.internet.defer import succeed

-from synapse.api.constants import MAX_DEPTH, EventTypes, Membership
+from synapse.api.constants import EventTypes, Membership, RoomVersions
 from synapse.api.errors import (
    AuthError,
    Codes,
@ -31,7 +31,6 @@ from synapse.api.errors import (
    SynapseError,
 )
 from synapse.api.urls import ConsentURIBuilder
-from synapse.crypto.event_signing import add_hashes_and_signatures
 from synapse.events.utils import serialize_event
 from synapse.events.validator import EventValidator
 from synapse.replication.http.send_event import ReplicationSendEventRestServlet
@ -278,9 +277,17 @@ class EventCreationHandler(object):
        """
        yield self.auth.check_auth_blocking(requester.user.to_string())

-        builder = self.event_builder_factory.new(event_dict)
+        if event_dict["type"] == EventTypes.Create and event_dict["state_key"] == "":
+            room_version = event_dict["content"]["room_version"]
+        else:
+            try:
+                room_version = yield self.store.get_room_version(event_dict["room_id"])
+            except NotFoundError:
+                raise AuthError(403, "Unknown room")

-        self.validator.validate_new(builder)
+        builder = self.event_builder_factory.new(room_version, event_dict)
+
+        self.validator.validate_builder(builder)

        if builder.type == EventTypes.Member:
            membership = builder.content.get("membership", None)
@ -318,6 +325,8 @@ class EventCreationHandler(object):
            prev_events_and_hashes=prev_events_and_hashes,
        )

+        self.validator.validate_new(event)
+
        defer.returnValue((event, context))

    def _is_exempt_from_privacy_policy(self, builder, requester):
@ -535,40 +544,19 @@ class EventCreationHandler(object):
            prev_events_and_hashes = \
                yield self.store.get_prev_events_for_room(builder.room_id)

-        if prev_events_and_hashes:
-            depth = max([d for _, _, d in prev_events_and_hashes]) + 1
-            # we cap depth of generated events, to ensure that they are not
-            # rejected by other servers (and so that they can be persisted in
-            # the db)
-            depth = min(depth, MAX_DEPTH)
-        else:
-            depth = 1
-
        prev_events = [
            (event_id, prev_hashes)
            for event_id, prev_hashes, _ in prev_events_and_hashes
        ]

-        builder.prev_events = prev_events
-        builder.depth = depth
-
-        context = yield self.state.compute_event_context(builder)
+        event = yield builder.build(
+            prev_event_ids=[p for p, _ in prev_events],
+        )
+        context = yield self.state.compute_event_context(event)
        if requester:
            context.app_service = requester.app_service

-        if builder.is_state():
-            builder.prev_state = yield self.store.add_event_hashes(
-                context.prev_state_events
-            )
-
-        yield self.auth.add_auth_events(builder, context)
-
-        signing_key = self.hs.config.signing_key[0]
-        add_hashes_and_signatures(
-            builder, self.server_name, signing_key
-        )
-
-        event = builder.build()
+        self.validator.validate_new(event)

        logger.debug(
            "Created event %s",
@ -603,8 +591,13 @@ class EventCreationHandler(object):
            extra_users (list(UserID)): Any extra users to notify about event
        """

+        if event.is_state() and (event.type, event.state_key) == (EventTypes.Create, ""):
+            room_version = event.content.get("room_version", RoomVersions.V1)
+        else:
+            room_version = yield self.store.get_room_version(event.room_id)
+
        try:
-            yield self.auth.check_from_context(event, context)
+            yield self.auth.check_from_context(room_version, event, context)
        except AuthError as err:
            logger.warn("Denying new event %r because %s", event, err)
            raise err
@ -752,7 +745,8 @@ class EventCreationHandler(object):
            auth_events = {
                (e.type, e.state_key): e for e in auth_events.values()
            }
-            if self.auth.check_redaction(event, auth_events=auth_events):
+            room_version = yield self.store.get_room_version(event.room_id)
+            if self.auth.check_redaction(room_version, event, auth_events=auth_events):
                original_event = yield self.store.get_event(
                    event.redacts,
                    check_redacted=False,
@ -766,6 +760,9 @@ class EventCreationHandler(object):
                        "You don't have permission to redact events"
                    )

+                # We've already checked.
+                event.internal_metadata.recheck_redaction = False
+
        if event.type == EventTypes.Create:
            prev_state_ids = yield context.get_prev_state_ids(self.store)
            if prev_state_ids:
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@ -123,9 +123,12 @@ class RoomCreationHandler(BaseHandler):
                    token_id=requester.access_token_id,
                )
            )
-            yield self.auth.check_from_context(tombstone_event, tombstone_context)
+            old_room_version = yield self.store.get_room_version(old_room_id)
+            yield self.auth.check_from_context(
+                old_room_version, tombstone_event, tombstone_context,
+            )

-            yield self.clone_exiting_room(
+            yield self.clone_existing_room(
                requester,
                old_room_id=old_room_id,
                new_room_id=new_room_id,
@ -230,7 +233,7 @@ class RoomCreationHandler(BaseHandler):
        )

    @defer.inlineCallbacks
-    def clone_exiting_room(
+    def clone_existing_room(
            self, requester, old_room_id, new_room_id, new_room_version,
            tombstone_event_id,
    ):
@ -262,6 +265,7 @@ class RoomCreationHandler(BaseHandler):

        initial_state = dict()

+        # Replicate relevant room events
        types_to_copy = (
            (EventTypes.JoinRules, ""),
            (EventTypes.Name, ""),
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@ -63,7 +63,7 @@ class RoomMemberHandler(object):
        self.directory_handler = hs.get_handlers().directory_handler
        self.registration_handler = hs.get_handlers().registration_handler
        self.profile_handler = hs.get_profile_handler()
-        self.event_creation_hander = hs.get_event_creation_handler()
+        self.event_creation_handler = hs.get_event_creation_handler()

        self.member_linearizer = Linearizer(name="member")

@ -161,6 +161,8 @@ class RoomMemberHandler(object):
        ratelimit=True,
        content=None,
    ):
+        user_id = target.to_string()
+
        if content is None:
            content = {}

@ -168,14 +170,14 @@ class RoomMemberHandler(object):
        if requester.is_guest:
            content["kind"] = "guest"

-        event, context = yield self.event_creation_hander.create_event(
+        event, context = yield self.event_creation_handler.create_event(
            requester,
            {
                "type": EventTypes.Member,
                "content": content,
                "room_id": room_id,
                "sender": requester.user.to_string(),
-                "state_key": target.to_string(),
+                "state_key": user_id,

                # For backwards compatibility:
                "membership": membership,
@ -186,14 +188,14 @@ class RoomMemberHandler(object):
        )

        # Check if this event matches the previous membership event for the user.
-        duplicate = yield self.event_creation_hander.deduplicate_state_event(
+        duplicate = yield self.event_creation_handler.deduplicate_state_event(
            event, context,
        )
        if duplicate is not None:
            # Discard the new event since this membership change is a no-op.
            defer.returnValue(duplicate)

-        yield self.event_creation_hander.handle_new_client_event(
+        yield self.event_creation_handler.handle_new_client_event(
            requester,
            event,
            context,
@ -204,12 +206,12 @@ class RoomMemberHandler(object):
        prev_state_ids = yield context.get_prev_state_ids(self.store)

        prev_member_event_id = prev_state_ids.get(
-            (EventTypes.Member, target.to_string()),
+            (EventTypes.Member, user_id),
            None
        )

        if event.membership == Membership.JOIN:
-            # Only fire user_joined_room if the user has acutally joined the
+            # Only fire user_joined_room if the user has actually joined the
            # room. Don't bother if the user is just changing their profile
            # info.
            newly_joined = True
@ -218,6 +220,18 @@ class RoomMemberHandler(object):
                newly_joined = prev_member_event.membership != Membership.JOIN
            if newly_joined:
                yield self._user_joined_room(target, room_id)
+
+            # Copy over direct message status and room tags if this is a join
+            # on an upgraded room
+
+            # Check if this is an upgraded room
+            predecessor = yield self.store.get_room_predecessor(room_id)
+
+            if predecessor:
+                # It is an upgraded room. Copy over old tags
+                self.copy_room_tags_and_direct_to_room(
+                    predecessor["room_id"], room_id, user_id,
+                )
        elif event.membership == Membership.LEAVE:
            if prev_member_event_id:
                prev_member_event = yield self.store.get_event(prev_member_event_id)
@ -226,6 +240,55 @@ class RoomMemberHandler(object):

        defer.returnValue(event)

+    @defer.inlineCallbacks
+    def copy_room_tags_and_direct_to_room(
+        self,
+        old_room_id,
+        new_room_id,
+        user_id,
+    ):
+        """Copies the tags and direct room state from one room to another.
+
+        Args:
+            old_room_id (str)
+            new_room_id (str)
+            user_id (str)
+
+        Returns:
+            Deferred[None]
+        """
+        # Retrieve user account data for predecessor room
+        user_account_data, _ = yield self.store.get_account_data_for_user(
+            user_id,
+        )
+
+        # Copy direct message state if applicable
+        direct_rooms = user_account_data.get("m.direct", {})
+
+        # Check which key this room is under
+        if isinstance(direct_rooms, dict):
+            for key, room_id_list in direct_rooms.items():
+                if old_room_id in room_id_list and new_room_id not in room_id_list:
+                    # Add new room_id to this key
+                    direct_rooms[key].append(new_room_id)
+
+                    # Save back to user's m.direct account data
+                    yield self.store.add_account_data_for_user(
+                        user_id, "m.direct", direct_rooms,
+                    )
+                    break
+
+        # Copy room tags if applicable
+        room_tags = yield self.store.get_tags_for_room(
+            user_id, old_room_id,
+        )
+
+        # Copy each room tag to the new room
+        for tag, tag_content in room_tags.items():
+            yield self.store.add_tag_to_room(
+                user_id, new_room_id, tag, tag_content
+            )
+
    @defer.inlineCallbacks
    def update_membership(
            self,
@ -493,7 +556,7 @@ class RoomMemberHandler(object):
        else:
            requester = synapse.types.create_requester(target_user)

-        prev_event = yield self.event_creation_hander.deduplicate_state_event(
+        prev_event = yield self.event_creation_handler.deduplicate_state_event(
            event, context,
        )
        if prev_event is not None:
@ -513,7 +576,7 @@ class RoomMemberHandler(object):
            if is_blocked:
                raise SynapseError(403, "This room has been blocked on this server")

-        yield self.event_creation_hander.handle_new_client_event(
+        yield self.event_creation_handler.handle_new_client_event(
            requester,
            event,
            context,
@ -527,7 +590,7 @@ class RoomMemberHandler(object):
        )

        if event.membership == Membership.JOIN:
-            # Only fire user_joined_room if the user has acutally joined the
+            # Only fire user_joined_room if the user has actually joined the
            # room. Don't bother if the user is just changing their profile
            # info.
            newly_joined = True
@ -755,7 +818,7 @@ class RoomMemberHandler(object):
            )
        )

-        yield self.event_creation_hander.create_and_send_nonmember_event(
+        yield self.event_creation_handler.create_and_send_nonmember_event(
            requester,
            {
                "type": EventTypes.ThirdPartyInvite,
@ -877,7 +940,8 @@ class RoomMemberHandler(object):
        # first member event?
        create_event_id = current_state_ids.get(("m.room.create", ""))
        if len(current_state_ids) == 1 and create_event_id:
-            defer.returnValue(self.hs.is_mine_id(create_event_id))
+            # We can only get here if we're in the process of creating the room
+            defer.returnValue(True)

        for etype, state_key in current_state_ids:
            if etype != EventTypes.Member or not self.hs.is_mine_id(state_key):
--- a/synapse/handlers/search.py
+++ b/synapse/handlers/search.py
@ -37,6 +37,41 @@ class SearchHandler(BaseHandler):
    def __init__(self, hs):
        super(SearchHandler, self).__init__(hs)

+    @defer.inlineCallbacks
+    def get_old_rooms_from_upgraded_room(self, room_id):
+        """Retrieves room IDs of old rooms in the history of an upgraded room.
+
+        We do so by checking the m.room.create event of the room for a
+        `predecessor` key. If it exists, we add the room ID to our return
+        list and then check that room for a m.room.create event and so on
+        until we can no longer find any more previous rooms.
+
+        The full list of all found rooms in then returned.
+
+        Args:
+            room_id (str): id of the room to search through.
+
+        Returns:
+            Deferred[iterable[unicode]]: predecessor room ids
+        """
+
+        historical_room_ids = []
+
+        while True:
+            predecessor = yield self.store.get_room_predecessor(room_id)
+
+            # If no predecessor, assume we've hit a dead end
+            if not predecessor:
+                break
+
+            # Add predecessor's room ID
+            historical_room_ids.append(predecessor["room_id"])
+
+            # Scan through the old room for further predecessors
+            room_id = predecessor["room_id"]
+
+        defer.returnValue(historical_room_ids)
+
    @defer.inlineCallbacks
    def search(self, user, content, batch=None):
        """Performs a full text search for a user.
@ -137,6 +172,18 @@ class SearchHandler(BaseHandler):
        )
        room_ids = set(r.room_id for r in rooms)

+        # If doing a subset of all rooms seearch, check if any of the rooms
+        # are from an upgraded room, and search their contents as well
+        if search_filter.rooms:
+            historical_room_ids = []
+            for room_id in search_filter.rooms:
+                # Add any previous rooms to the search if they exist
+                ids = yield self.get_old_rooms_from_upgraded_room(room_id)
+                historical_room_ids += ids
+
+            # Prevent any historical events from being filtered
+            search_filter = search_filter.with_room_ids(historical_room_ids)
+
        room_ids = search_filter.filter_rooms(room_ids)

        if batch_group == "room_id":
--- a/synapse/http/federation/matrix_federation_agent.py
+++ b/synapse/http/federation/matrix_federation_agent.py
@ -12,16 +12,19 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import json
 import logging

+import attr
+from netaddr import IPAddress
 from zope.interface import implementer

 from twisted.internet import defer
 from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
-from twisted.web.client import URI, Agent, HTTPConnectionPool
+from twisted.web.client import URI, Agent, HTTPConnectionPool, readBody
+from twisted.web.http_headers import Headers
 from twisted.web.iweb import IAgent

-from synapse.http.endpoint import parse_server_name
 from synapse.http.federation.srv_resolver import SrvResolver, pick_server_from_list
 from synapse.util.logcontext import make_deferred_yieldable

@ -41,13 +44,19 @@ class MatrixFederationAgent(object):
        tls_client_options_factory (ClientTLSOptionsFactory|None):
            factory to use for fetching client tls options, or none to disable TLS.

+        _well_known_tls_policy (IPolicyForHTTPS|None):
+            TLS policy to use for fetching .well-known files. None to use a default
+            (browser-like) implementation.
+
        srv_resolver (SrvResolver|None):
            SRVResolver impl to use for looking up SRV records. None to use a default
            implementation.
    """

    def __init__(
-        self, reactor, tls_client_options_factory, _srv_resolver=None,
+        self, reactor, tls_client_options_factory,
+        _well_known_tls_policy=None,
+        _srv_resolver=None,
    ):
        self._reactor = reactor
        self._tls_client_options_factory = tls_client_options_factory
@ -60,6 +69,14 @@ class MatrixFederationAgent(object):
        self._pool.maxPersistentPerHost = 5
        self._pool.cachedConnectionTimeout = 2 * 60

+        agent_args = {}
+        if _well_known_tls_policy is not None:
+            # the param is called 'contextFactory', but actually passing a
+            # contextfactory is deprecated, and it expects an IPolicyForHTTPS.
+            agent_args['contextFactory'] = _well_known_tls_policy
+        _well_known_agent = Agent(self._reactor, pool=self._pool, **agent_args)
+        self._well_known_agent = _well_known_agent
+
    @defer.inlineCallbacks
    def request(self, method, uri, headers=None, bodyProducer=None):
        """
@ -85,35 +102,39 @@ class MatrixFederationAgent(object):
                response from being received (including problems that prevent the request
                from being sent).
        """
+        parsed_uri = URI.fromBytes(uri, defaultPort=-1)
+        res = yield self._route_matrix_uri(parsed_uri)

-        parsed_uri = URI.fromBytes(uri)
-        server_name_bytes = parsed_uri.netloc
-        host, port = parse_server_name(server_name_bytes.decode("ascii"))
-
+        # set up the TLS connection params
+        #
        # XXX disabling TLS is really only supported here for the benefit of the
        # unit tests. We should make the UTs cope with TLS rather than having to make
        # the code support the unit tests.
        if self._tls_client_options_factory is None:
            tls_options = None
        else:
-            tls_options = self._tls_client_options_factory.get_options(host)
+            tls_options = self._tls_client_options_factory.get_options(
+                res.tls_server_name.decode("ascii")
+            )

-        if port is not None:
-            target = (host, port)
+        # make sure that the Host header is set correctly
+        if headers is None:
+            headers = Headers()
        else:
-            service_name = b"_matrix._tcp.%s" % (server_name_bytes, )
-            server_list = yield self._srv_resolver.resolve_service(service_name)
-            if not server_list:
-                target = (host, 8448)
-                logger.debug("No SRV record for %s, using %s", host, target)
-            else:
-                target = pick_server_from_list(server_list)
+            headers = headers.copy()
+
+        if not headers.hasHeader(b'host'):
+            headers.addRawHeader(b'host', res.host_header)

        class EndpointFactory(object):
            @staticmethod
            def endpointForURI(_uri):
-                logger.info("Connecting to %s:%s", target[0], target[1])
-                ep = HostnameEndpoint(self._reactor, host=target[0], port=target[1])
+                logger.info(
+                    "Connecting to %s:%i",
+                    res.target_host.decode("ascii"),
+                    res.target_port,
+                )
+                ep = HostnameEndpoint(self._reactor, res.target_host, res.target_port)
                if tls_options is not None:
                    ep = wrapClientTLS(tls_options, ep)
                return ep
@ -123,3 +144,191 @@ class MatrixFederationAgent(object):
            agent.request(method, uri, headers, bodyProducer)
        )
        defer.returnValue(res)
+
+    @defer.inlineCallbacks
+    def _route_matrix_uri(self, parsed_uri, lookup_well_known=True):
+        """Helper for `request`: determine the routing for a Matrix URI
+
+        Args:
+            parsed_uri (twisted.web.client.URI): uri to route. Note that it should be
+                parsed with URI.fromBytes(uri, defaultPort=-1) to set the `port` to -1
+                if there is no explicit port given.
+
+            lookup_well_known (bool): True if we should look up the .well-known file if
+                there is no SRV record.
+
+        Returns:
+            Deferred[_RoutingResult]
+        """
+        # check for an IP literal
+        try:
+            ip_address = IPAddress(parsed_uri.host.decode("ascii"))
+        except Exception:
+            # not an IP address
+            ip_address = None
+
+        if ip_address:
+            port = parsed_uri.port
+            if port == -1:
+                port = 8448
+            defer.returnValue(_RoutingResult(
+                host_header=parsed_uri.netloc,
+                tls_server_name=parsed_uri.host,
+                target_host=parsed_uri.host,
+                target_port=port,
+            ))
+
+        if parsed_uri.port != -1:
+            # there is an explicit port
+            defer.returnValue(_RoutingResult(
+                host_header=parsed_uri.netloc,
+                tls_server_name=parsed_uri.host,
+                target_host=parsed_uri.host,
+                target_port=parsed_uri.port,
+            ))
+
+        # try a SRV lookup
+        service_name = b"_matrix._tcp.%s" % (parsed_uri.host,)
+        server_list = yield self._srv_resolver.resolve_service(service_name)
+
+        if not server_list and lookup_well_known:
+            # try a .well-known lookup
+            well_known_server = yield self._get_well_known(parsed_uri.host)
+
+            if well_known_server:
+                # if we found a .well-known, start again, but don't do another
+                # .well-known lookup.
+
+                # parse the server name in the .well-known response into host/port.
+                # (This code is lifted from twisted.web.client.URI.fromBytes).
+                if b':' in well_known_server:
+                    well_known_host, well_known_port = well_known_server.rsplit(b':', 1)
+                    try:
+                        well_known_port = int(well_known_port)
+                    except ValueError:
+                        # the part after the colon could not be parsed as an int
+                        # - we assume it is an IPv6 literal with no port (the closing
+                        # ']' stops it being parsed as an int)
+                        well_known_host, well_known_port = well_known_server, -1
+                else:
+                    well_known_host, well_known_port = well_known_server, -1
+
+                new_uri = URI(
+                    scheme=parsed_uri.scheme,
+                    netloc=well_known_server,
+                    host=well_known_host,
+                    port=well_known_port,
+                    path=parsed_uri.path,
+                    params=parsed_uri.params,
+                    query=parsed_uri.query,
+                    fragment=parsed_uri.fragment,
+                )
+
+                res = yield self._route_matrix_uri(new_uri, lookup_well_known=False)
+                defer.returnValue(res)
+
+        if not server_list:
+            target_host = parsed_uri.host
+            port = 8448
+            logger.debug(
+                "No SRV record for %s, using %s:%i",
+                parsed_uri.host.decode("ascii"), target_host.decode("ascii"), port,
+            )
+        else:
+            target_host, port = pick_server_from_list(server_list)
+            logger.debug(
+                "Picked %s:%i from SRV records for %s",
+                target_host.decode("ascii"), port, parsed_uri.host.decode("ascii"),
+            )
+
+        defer.returnValue(_RoutingResult(
+            host_header=parsed_uri.netloc,
+            tls_server_name=parsed_uri.host,
+            target_host=target_host,
+            target_port=port,
+        ))
+
+    @defer.inlineCallbacks
+    def _get_well_known(self, server_name):
+        """Attempt to fetch and parse a .well-known file for the given server
+
+        Args:
+            server_name (bytes): name of the server, from the requested url
+
+        Returns:
+            Deferred[bytes|None]: either the new server name, from the .well-known, or
+                None if there was no .well-known file.
+        """
+        # FIXME: add a cache
+
+        uri = b"https://%s/.well-known/matrix/server" % (server_name, )
+        uri_str = uri.decode("ascii")
+        logger.info("Fetching %s", uri_str)
+        try:
+            response = yield make_deferred_yieldable(
+                self._well_known_agent.request(b"GET", uri),
+            )
+        except Exception as e:
+            logger.info("Connection error fetching %s: %s", uri_str, e)
+            defer.returnValue(None)
+
+        body = yield make_deferred_yieldable(readBody(response))
+
+        if response.code != 200:
+            logger.info("Error response %i from %s", response.code, uri_str)
+            defer.returnValue(None)
+
+        try:
+            parsed_body = json.loads(body.decode('utf-8'))
+            logger.info("Response from .well-known: %s", parsed_body)
+            if not isinstance(parsed_body, dict):
+                raise Exception("not a dict")
+            if "m.server" not in parsed_body:
+                raise Exception("Missing key 'm.server'")
+        except Exception as e:
+            raise Exception("invalid .well-known response from %s: %s" % (uri_str, e,))
+        defer.returnValue(parsed_body["m.server"].encode("ascii"))
+
+
+@attr.s
+class _RoutingResult(object):
+    """The result returned by `_route_matrix_uri`.
+
+    Contains the parameters needed to direct a federation connection to a particular
+    server.
+
+    Where a SRV record points to several servers, this object contains a single server
+    chosen from the list.
+    """
+
+    host_header = attr.ib()
+    """
+    The value we should assign to the Host header (host:port from the matrix
+    URI, or .well-known).
+
+    :type: bytes
+    """
+
+    tls_server_name = attr.ib()
+    """
+    The server name we should set in the SNI (typically host, without port, from the
+    matrix URI or .well-known)
+
+    :type: bytes
+    """
+
+    target_host = attr.ib()
+    """
+    The hostname (or IP literal) we should route the TCP connection to (the target of the
+    SRV record, or the hostname from the URL/.well-known)
+
+    :type: bytes
+    """
+
+    target_port = attr.ib()
+    """
+    The port we should route the TCP connection to (the target of the SRV record, or
+    the port from the URL/.well-known, or 8448)
+
+    :type: int
+    """
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@ -255,7 +255,6 @@ class MatrixFederationHttpClient(object):

        headers_dict = {
            b"User-Agent": [self.version_string_bytes],
-            b"Host": [destination_bytes],
        }

        with limiter:
--- a/synapse/replication/http/federation.py
+++ b/synapse/replication/http/federation.py
@ -17,7 +17,7 @@ import logging

 from twisted.internet import defer

-from synapse.events import FrozenEvent
+from synapse.events import event_type_from_format_version
 from synapse.events.snapshot import EventContext
 from synapse.http.servlet import parse_json_object_from_request
 from synapse.replication.http._base import ReplicationEndpoint
@ -70,6 +70,7 @@ class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):

            event_payloads.append({
                "event": event.get_pdu_json(),
+                "event_format_version": event.format_version,
                "internal_metadata": event.internal_metadata.get_dict(),
                "rejected_reason": event.rejected_reason,
                "context": serialized_context,
@ -94,9 +95,12 @@ class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):
            event_and_contexts = []
            for event_payload in event_payloads:
                event_dict = event_payload["event"]
+                format_ver = event_payload["event_format_version"]
                internal_metadata = event_payload["internal_metadata"]
                rejected_reason = event_payload["rejected_reason"]
-                event = FrozenEvent(event_dict, internal_metadata, rejected_reason)
+
+                EventType = event_type_from_format_version(format_ver)
+                event = EventType(event_dict, internal_metadata, rejected_reason)

                context = yield EventContext.deserialize(
                    self.store, event_payload["context"],
--- a/synapse/replication/http/send_event.py
+++ b/synapse/replication/http/send_event.py
@ -17,7 +17,7 @@ import logging

 from twisted.internet import defer

-from synapse.events import FrozenEvent
+from synapse.events import event_type_from_format_version
 from synapse.events.snapshot import EventContext
 from synapse.http.servlet import parse_json_object_from_request
 from synapse.replication.http._base import ReplicationEndpoint
@ -74,6 +74,7 @@ class ReplicationSendEventRestServlet(ReplicationEndpoint):

        payload = {
            "event": event.get_pdu_json(),
+            "event_format_version": event.format_version,
            "internal_metadata": event.internal_metadata.get_dict(),
            "rejected_reason": event.rejected_reason,
            "context": serialized_context,
@ -90,9 +91,12 @@ class ReplicationSendEventRestServlet(ReplicationEndpoint):
            content = parse_json_object_from_request(request)

            event_dict = content["event"]
+            format_ver = content["event_format_version"]
            internal_metadata = content["internal_metadata"]
            rejected_reason = content["rejected_reason"]
-            event = FrozenEvent(event_dict, internal_metadata, rejected_reason)
+
+            EventType = event_type_from_format_version(format_ver)
+            event = EventType(event_dict, internal_metadata, rejected_reason)

            requester = Requester.deserialize(self.store, content["requester"])
            context = yield EventContext.deserialize(self.store, content["context"])
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@ -89,7 +89,7 @@ class RoomStateEventRestServlet(ClientV1RestServlet):
    def __init__(self, hs):
        super(RoomStateEventRestServlet, self).__init__(hs)
        self.handlers = hs.get_handlers()
-        self.event_creation_hander = hs.get_event_creation_handler()
+        self.event_creation_handler = hs.get_event_creation_handler()
        self.room_member_handler = hs.get_room_member_handler()
        self.message_handler = hs.get_message_handler()

@ -172,7 +172,7 @@ class RoomStateEventRestServlet(ClientV1RestServlet):
                content=content,
            )
        else:
-            event = yield self.event_creation_hander.create_and_send_nonmember_event(
+            event = yield self.event_creation_handler.create_and_send_nonmember_event(
                requester,
                event_dict,
                txn_id=txn_id,
@ -189,7 +189,7 @@ class RoomSendEventRestServlet(ClientV1RestServlet):

    def __init__(self, hs):
        super(RoomSendEventRestServlet, self).__init__(hs)
-        self.event_creation_hander = hs.get_event_creation_handler()
+        self.event_creation_handler = hs.get_event_creation_handler()

    def register(self, http_server):
        # /rooms/$roomid/send/$event_type[/$txn_id]
@ -211,7 +211,7 @@ class RoomSendEventRestServlet(ClientV1RestServlet):
        if b'ts' in request.args and requester.app_service:
            event_dict['origin_server_ts'] = parse_integer(request, "ts", 0)

-        event = yield self.event_creation_hander.create_and_send_nonmember_event(
+        event = yield self.event_creation_handler.create_and_send_nonmember_event(
            requester,
            event_dict,
            txn_id=txn_id,
--- a/synapse/rest/consent/consent_resource.py
+++ b/synapse/rest/consent/consent_resource.py
@ -101,16 +101,7 @@ class ConsentResource(Resource):
                "missing in config file.",
            )

-        # daemonize changes the cwd to /, so make the path absolute now.
-        consent_template_directory = path.abspath(
-            hs.config.user_consent_template_dir,
-        )
-        if not path.isdir(consent_template_directory):
-            raise ConfigError(
-                "Could not find template directory '%s'" % (
-                    consent_template_directory,
-                ),
-            )
+        consent_template_directory = hs.config.user_consent_template_dir

        loader = jinja2.FileSystemLoader(consent_template_directory)
        self._jinja_env = jinja2.Environment(
--- a/synapse/server.py
+++ b/synapse/server.py
@ -355,10 +355,7 @@ class HomeServer(object):
        return Keyring(self)

    def build_event_builder_factory(self):
-        return EventBuilderFactory(
-            clock=self.get_clock(),
-            hostname=self.hostname,
-        )
+        return EventBuilderFactory(self)

    def build_filtering(self):
        return Filtering(self)
--- a/synapse/state/init.py
+++ b/synapse/state/init.py
@ -608,10 +608,10 @@ def resolve_events_with_store(room_version, state_sets, event_map, state_res_sto
            state_sets, event_map, state_res_store.get_events,
        )
    elif room_version in (
-        RoomVersions.VDH_TEST, RoomVersions.STATE_V2_TEST, RoomVersions.V2,
+        RoomVersions.STATE_V2_TEST, RoomVersions.V2, RoomVersions.V3,
    ):
        return v2.resolve_events_with_store(
-            state_sets, event_map, state_res_store,
+            room_version, state_sets, event_map, state_res_store,
        )
    else:
        # This should only happen if we added a version but forgot to add it to
--- a/synapse/state/v1.py
+++ b/synapse/state/v1.py
@ -21,7 +21,7 @@ from six import iteritems, iterkeys, itervalues
 from twisted.internet import defer

 from synapse import event_auth
-from synapse.api.constants import EventTypes
+from synapse.api.constants import EventTypes, RoomVersions
 from synapse.api.errors import AuthError

 logger = logging.getLogger(__name__)
@ -274,7 +274,11 @@ def _resolve_auth_events(events, auth_events):
        auth_events[(prev_event.type, prev_event.state_key)] = prev_event
        try:
            # The signatures have already been checked at this point
-            event_auth.check(event, auth_events, do_sig_check=False, do_size_check=False)
+            event_auth.check(
+                RoomVersions.V1, event, auth_events,
+                do_sig_check=False,
+                do_size_check=False,
+            )
            prev_event = event
        except AuthError:
            return prev_event
@ -286,7 +290,11 @@ def _resolve_normal_events(events, auth_events):
    for event in _ordered_events(events):
        try:
            # The signatures have already been checked at this point
-            event_auth.check(event, auth_events, do_sig_check=False, do_size_check=False)
+            event_auth.check(
+                RoomVersions.V1, event, auth_events,
+                do_sig_check=False,
+                do_size_check=False,
+            )
            return event
        except AuthError:
            pass
--- a/synapse/state/v2.py
+++ b/synapse/state/v2.py
@ -29,10 +29,12 @@ logger = logging.getLogger(__name__)


@defer.inlineCallbacks
-def resolve_events_with_store(state_sets, event_map, state_res_store):
+def resolve_events_with_store(room_version, state_sets, event_map, state_res_store):
    """Resolves the state using the v2 state resolution algorithm

    Args:
+        room_version (str): The room version
+
        state_sets(list): List of dicts of (type, state_key) -> event_id,
            which are the different state groups to resolve.

@ -104,7 +106,7 @@ def resolve_events_with_store(state_sets, event_map, state_res_store):

    # Now sequentially auth each one
    resolved_state = yield _iterative_auth_checks(
-        sorted_power_events, unconflicted_state, event_map,
+        room_version, sorted_power_events, unconflicted_state, event_map,
        state_res_store,
    )

@ -129,7 +131,7 @@ def resolve_events_with_store(state_sets, event_map, state_res_store):
    logger.debug("resolving remaining events")

    resolved_state = yield _iterative_auth_checks(
-        leftover_events, resolved_state, event_map,
+        room_version, leftover_events, resolved_state, event_map,
        state_res_store,
    )

@ -350,11 +352,13 @@ def _reverse_topological_power_sort(event_ids, event_map, state_res_store, auth_


@defer.inlineCallbacks
-def _iterative_auth_checks(event_ids, base_state, event_map, state_res_store):
+def _iterative_auth_checks(room_version, event_ids, base_state, event_map,
+                           state_res_store):
    """Sequentially apply auth checks to each event in given list, updating the
    state as it goes along.

    Args:
+        room_version (str)
        event_ids (list[str]): Ordered list of events to apply auth checks to
        base_state (dict[tuple[str, str], str]): The set of state to start with
        event_map (dict[str,FrozenEvent])
@ -385,7 +389,7 @@ def _iterative_auth_checks(event_ids, base_state, event_map, state_res_store):

        try:
            event_auth.check(
-                event, auth_events,
+                room_version, event, auth_events,
                do_sig_check=False,
                do_size_check=False
            )
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@ -27,7 +27,7 @@ from twisted.internet import defer

 from synapse.api.errors import StoreError
 from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.storage.engines import PostgresEngine
+from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 from synapse.util.caches.descriptors import Cache
 from synapse.util.logcontext import LoggingContext, PreserveLoggingContext
 from synapse.util.stringutils import exception_to_unicode
@ -196,6 +196,12 @@ class SQLBaseStore(object):
        # A set of tables that are not safe to use native upserts in.
        self._unsafe_to_upsert_tables = {"user_ips"}

+        # We add the user_directory_search table to the blacklist on SQLite
+        # because the existing search table does not have an index, making it
+        # unsafe to use native upserts.
+        if isinstance(self.database_engine, Sqlite3Engine):
+            self._unsafe_to_upsert_tables.add("user_directory_search")
+
        if self.database_engine.can_native_upsert:
            # Check ASAP (and then later, every 1s) to see if we have finished
            # background updates of tables that aren't safe to update.
@ -230,7 +236,7 @@ class SQLBaseStore(object):
            self._unsafe_to_upsert_tables.discard("user_ips")

        # If there's any tables left to check, reschedule to run.
-        if self._unsafe_to_upsert_tables:
+        if updates:
            self._clock.call_later(
                15.0,
                run_as_background_process,
--- a/synapse/storage/background_updates.py
+++ b/synapse/storage/background_updates.py
@ -240,7 +240,7 @@ class BackgroundUpdateStore(SQLBaseStore):
        * An integer count of the number of items to update in this batch.

        The handler should return a deferred integer count of items updated.
-        The hander is responsible for updating the progress of the update.
+        The handler is responsible for updating the progress of the update.

        Args:
            update_name(str): The name of the update that this code handles.
--- a/synapse/storage/engines/sqlite.py
+++ b/synapse/storage/engines/sqlite.py
@ -15,7 +15,6 @@

 import struct
 import threading
-from sqlite3 import sqlite_version_info

 from synapse.storage.prepare_database import prepare_database

@ -37,7 +36,7 @@ class Sqlite3Engine(object):
        Do we support native UPSERTs? This requires SQLite3 3.24+, plus some
        more work we haven't done yet to tell what was inserted vs updated.
        """
-        return sqlite_version_info >= (3, 24, 0)
+        return self.module.sqlite_version_info >= (3, 24, 0)

    def check_database(self, txn):
        pass
--- a/synapse/storage/event_federation.py
+++ b/synapse/storage/event_federation.py
@ -125,6 +125,29 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore,

        return dict(txn)

+    @defer.inlineCallbacks
+    def get_max_depth_of(self, event_ids):
+        """Returns the max depth of a set of event IDs
+
+        Args:
+            event_ids (list[str])
+
+        Returns
+            Deferred[int]
+        """
+        rows = yield self._simple_select_many_batch(
+            table="events",
+            column="event_id",
+            iterable=event_ids,
+            retcols=("depth",),
+            desc="get_max_depth_of",
+        )
+
+        if not rows:
+            defer.returnValue(0)
+        else:
+            defer.returnValue(max(row["depth"] for row in rows))
+
    def _get_oldest_events_in_room_txn(self, txn, room_id):
        return self._simple_select_onecol_txn(
            txn,
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@ -1268,6 +1268,7 @@ class EventsStore(StateGroupWorkerStore, EventFederationStore, EventsWorkerStore
                        event.internal_metadata.get_dict()
                    ),
                    "json": encode_json(event_dict(event)),
+                    "format_version": event.format_version,
                }
                for event, _ in events_and_contexts
            ],
--- a/synapse/storage/events_worker.py
+++ b/synapse/storage/events_worker.py
@ -21,13 +21,14 @@ from canonicaljson import json

 from twisted.internet import defer

+from synapse.api.constants import EventFormatVersions, EventTypes
 from synapse.api.errors import NotFoundError
+from synapse.events import FrozenEvent, event_type_from_format_version  # noqa: F401
 # these are only included to make the type annotations work
-from synapse.events import EventBase  # noqa: F401
-from synapse.events import FrozenEvent
 from synapse.events.snapshot import EventContext  # noqa: F401
 from synapse.events.utils import prune_event
 from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.types import get_domain_from_id
 from synapse.util.logcontext import (
    LoggingContext,
    PreserveLoggingContext,
@ -162,7 +163,6 @@ class EventsWorkerStore(SQLBaseStore):

            missing_events = yield self._enqueue_events(
                missing_events_ids,
-                check_redacted=check_redacted,
                allow_rejected=allow_rejected,
            )

@ -174,6 +174,29 @@ class EventsWorkerStore(SQLBaseStore):
            if not entry:
                continue

+            # Starting in room version v3, some redactions need to be rechecked if we
+            # didn't have the redacted event at the time, so we recheck on read
+            # instead.
+            if not allow_rejected and entry.event.type == EventTypes.Redaction:
+                if entry.event.internal_metadata.need_to_check_redaction():
+                    orig = yield self.get_event(
+                        entry.event.redacts,
+                        allow_none=True,
+                        allow_rejected=True,
+                        get_prev_content=False,
+                    )
+                    expected_domain = get_domain_from_id(entry.event.sender)
+                    if orig and get_domain_from_id(orig.sender) == expected_domain:
+                        # This redaction event is allowed. Mark as not needing a
+                        # recheck.
+                        entry.event.internal_metadata.recheck_redaction = False
+                    else:
+                        # We don't have the event that is being redacted, so we
+                        # assume that the event isn't authorized for now. (If we
+                        # later receive the event, then we will always redact
+                        # it anyway, since we have this redaction)
+                        continue
+
            if allow_rejected or not entry.event.rejected_reason:
                if check_redacted and entry.redacted_event:
                    event = entry.redacted_event
@ -310,7 +333,7 @@ class EventsWorkerStore(SQLBaseStore):
                    self.hs.get_reactor().callFromThread(fire, event_list, e)

    @defer.inlineCallbacks
-    def _enqueue_events(self, events, check_redacted=True, allow_rejected=False):
+    def _enqueue_events(self, events, allow_rejected=False):
        """Fetches events from the database using the _event_fetch_list. This
        allows batch and bulk fetching of events - it allows us to fetch events
        without having to create a new transaction for each request for events.
@ -353,6 +376,7 @@ class EventsWorkerStore(SQLBaseStore):
                    self._get_event_from_row,
                    row["internal_metadata"], row["json"], row["redacts"],
                    rejected_reason=row["rejects"],
+                    format_version=row["format_version"],
                )
                for row in rows
            ],
@ -377,6 +401,7 @@ class EventsWorkerStore(SQLBaseStore):
                " e.event_id as event_id, "
                " e.internal_metadata,"
                " e.json,"
+                " e.format_version, "
                " r.redacts as redacts,"
                " rej.event_id as rejects "
                " FROM event_json as e"
@ -392,7 +417,7 @@ class EventsWorkerStore(SQLBaseStore):

    @defer.inlineCallbacks
    def _get_event_from_row(self, internal_metadata, js, redacted,
-                            rejected_reason=None):
+                            format_version, rejected_reason=None):
        with Measure(self._clock, "_get_event_from_row"):
            d = json.loads(js)
            internal_metadata = json.loads(internal_metadata)
@ -405,8 +430,13 @@ class EventsWorkerStore(SQLBaseStore):
                    desc="_get_event_from_row_rejected_reason",
                )

-            original_ev = FrozenEvent(
-                d,
+            if format_version is None:
+                # This means that we stored the event before we had the concept
+                # of a event format version, so it must be a V1 event.
+                format_version = EventFormatVersions.V1
+
+            original_ev = event_type_from_format_version(format_version)(
+                event_dict=d,
                internal_metadata_dict=internal_metadata,
                rejected_reason=rejected_reason,
            )
@ -436,6 +466,19 @@ class EventsWorkerStore(SQLBaseStore):
                    # will serialise this field correctly
                    redacted_event.unsigned["redacted_because"] = because

+                    # Starting in room version v3, some redactions need to be
+                    # rechecked if we didn't have the redacted event at the
+                    # time, so we recheck on read instead.
+                    if because.internal_metadata.need_to_check_redaction():
+                        expected_domain = get_domain_from_id(original_ev.sender)
+                        if get_domain_from_id(because.sender) == expected_domain:
+                            # This redaction event is allowed. Mark as not needing a
+                            # recheck.
+                            because.internal_metadata.recheck_redaction = False
+                        else:
+                            # Senders don't match, so the event isn't actually redacted
+                            redacted_event = None
+
            cache_entry = _EventCacheEntry(
                event=original_ev,
                redacted_event=redacted_event,
--- a/synapse/storage/monthly_active_users.py
+++ b/synapse/storage/monthly_active_users.py
@ -197,15 +197,21 @@ class MonthlyActiveUsersStore(SQLBaseStore):
        if is_support:
            return

-        is_insert = yield self.runInteraction(
+        yield self.runInteraction(
            "upsert_monthly_active_user", self.upsert_monthly_active_user_txn,
            user_id
        )

-        if is_insert:
-            self.user_last_seen_monthly_active.invalidate((user_id,))
+        user_in_mau = self.user_last_seen_monthly_active.cache.get(
+            (user_id,),
+            None,
+            update_metrics=False
+        )
+        if user_in_mau is None:
            self.get_monthly_active_count.invalidate(())

+        self.user_last_seen_monthly_active.invalidate((user_id,))
+
    def upsert_monthly_active_user_txn(self, txn, user_id):
        """Updates or inserts monthly active user member

--- a/synapse/storage/roommember.py
+++ b/synapse/storage/roommember.py
@ -588,12 +588,12 @@ class RoomMemberStore(RoomMemberWorkerStore):
            )

            # We update the local_invites table only if the event is "current",
-            # i.e., its something that has just happened.
-            # The only current event that can also be an outlier is if its an
-            # invite that has come in across federation.
+            # i.e., its something that has just happened. If the event is an
+            # outlier it is only current if its an "out of band membership",
+            # like a remote invite or a rejection of a remote invite.
            is_new_state = not backfilled and (
                not event.internal_metadata.is_outlier()
-                or event.internal_metadata.is_invite_from_remote()
+                or event.internal_metadata.is_out_of_band_membership()
            )
            is_mine = self.hs.is_mine_id(event.state_key)
            if is_new_state and is_mine:
--- a/synapse/storage/schema/delta/53/event_format_version.sql
+++ b/synapse/storage/schema/delta/53/event_format_version.sql
@ -0,0 +1,16 @@
+/* Copyright 2019 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+ALTER TABLE event_json ADD COLUMN format_version INTEGER;
--- a/Show More
+++ b/Show More
				`@ -0,0 +1 @@`
				`Implement MSC1708 (.well-known routing for server-server federation)`
				`@ -1 +0,0 @@`
				`Refactor 'sign_request' as 'build_auth_headers'`
				`@ -1 +0,0 @@`
				`Remove redundant federation connection wrapping code`
				`@ -0,0 +1 @@`
				`Copy over whether a room is a direct message and any associated room tags on room upgrade.`
				`@ -0,0 +1 @@`
				`Search now includes results from predecessor rooms after a room upgrade.`
				`@ -1 +0,0 @@`
				`Remove redundant SynapseKeyClientProtocol magic`
				`@ -0,0 +1 @@`
				`Add infrastructure to support different event formats`
				`@ -0,0 +1 @@`
				`Synapse will now take advantage of native UPSERT functionality in PostgreSQL 9.5+ and SQLite 3.24+.`
				`@ -0,0 +1 @@`
				`Fix quoting for allowed_local_3pids example config`
				`@ -0,0 +1 @@`
				`Remove deprecated --process-dependency-links option from UPGRADE.rst`