diff --git a/changelog.d/6848.bugfix b/changelog.d/6848.bugfix
new file mode 100644
index 000000000..65688e5d5
--- /dev/null
+++ b/changelog.d/6848.bugfix
@@ -0,0 +1 @@
+Fix detecting unknown devices from remote encrypted events.
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 0ade47e62..cc8577552 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -77,12 +77,11 @@ class EventTypes(object):
     Aliases = "m.room.aliases"
     Redaction = "m.room.redaction"
     ThirdPartyInvite = "m.room.third_party_invite"
-    Encryption = "m.room.encryption"
     RelatedGroups = "m.room.related_groups"
 
     RoomHistoryVisibility = "m.room.history_visibility"
     CanonicalAlias = "m.room.canonical_alias"
-    Encryption = "m.room.encryption"
+    Encrypted = "m.room.encrypted"
     RoomAvatar = "m.room.avatar"
     RoomEncryption = "m.room.encryption"
     GuestAccess = "m.room.guest_access"
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index c86d3177e..488200a2d 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -752,7 +752,7 @@ class FederationHandler(BaseHandler):
 
         # For encrypted messages we check that we know about the sending device,
         # if we don't then we mark the device cache for that user as stale.
-        if event.type == EventTypes.Encryption:
+        if event.type == EventTypes.Encrypted:
             device_id = event.content.get("device_id")
             if device_id is not None:
                 cached_devices = await self.store.get_cached_devices_for_user(
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 138239955..b609a65f4 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -360,7 +360,7 @@ class RoomCreationHandler(BaseHandler):
             (EventTypes.RoomHistoryVisibility, ""),
             (EventTypes.GuestAccess, ""),
             (EventTypes.RoomAvatar, ""),
-            (EventTypes.Encryption, ""),
+            (EventTypes.RoomEncryption, ""),
             (EventTypes.ServerACL, ""),
             (EventTypes.RelatedGroups, ""),
             (EventTypes.PowerLevels, ""),
diff --git a/synapse/handlers/stats.py b/synapse/handlers/stats.py
index 7f7d56390..68e6edace 100644
--- a/synapse/handlers/stats.py
+++ b/synapse/handlers/stats.py
@@ -286,7 +286,7 @@ class StatsHandler(StateDeltasHandler):
                 room_state["history_visibility"] = event_content.get(
                     "history_visibility"
                 )
-            elif typ == EventTypes.Encryption:
+            elif typ == EventTypes.RoomEncryption:
                 room_state["encryption"] = event_content.get("algorithm")
             elif typ == EventTypes.Name:
                 room_state["name"] = event_content.get("name")
diff --git a/synapse/storage/data_stores/main/stats.py b/synapse/storage/data_stores/main/stats.py
index 7bc186e9a..7af1495e4 100644
--- a/synapse/storage/data_stores/main/stats.py
+++ b/synapse/storage/data_stores/main/stats.py
@@ -744,7 +744,7 @@ class StatsStore(StateDeltasStore):
                     EventTypes.Create,
                     EventTypes.JoinRules,
                     EventTypes.RoomHistoryVisibility,
-                    EventTypes.Encryption,
+                    EventTypes.RoomEncryption,
                     EventTypes.Name,
                     EventTypes.Topic,
                     EventTypes.RoomAvatar,
@@ -816,7 +816,7 @@ class StatsStore(StateDeltasStore):
                 room_state["history_visibility"] = event.content.get(
                     "history_visibility"
                 )
-            elif event.type == EventTypes.Encryption:
+            elif event.type == EventTypes.RoomEncryption:
                 room_state["encryption"] = event.content.get("algorithm")
             elif event.type == EventTypes.Name:
                 room_state["name"] = event.content.get("name")