diff --git a/CHANGES.md b/CHANGES.md
index 74125613f..01488f1e9 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,68 @@
+# Synapse 1.90.0rc1 (2023-08-08)
+
+### Features
+
+- Scope transaction IDs to devices (implement [MSC3970](https://github.com/matrix-org/matrix-spec-proposals/pull/3970)). ([\#15629](https://github.com/matrix-org/synapse/issues/15629))
+- Remove old rows from the `cache_invalidation_stream_by_instance` table automatically (this table is unused in SQLite). ([\#15868](https://github.com/matrix-org/synapse/issues/15868))
+
+### Bugfixes
+
+- Fix bug where purging history and paginating simultaneously could lead to database corruption when using workers. ([\#15791](https://github.com/matrix-org/synapse/issues/15791))
+- Fix 404 not found code returned on profile endpoint when the display name is empty but not the avatar URL. ([\#16012](https://github.com/matrix-org/synapse/issues/16012))
+- Remove leading and trailing spaces when setting a display name. ([\#16031](https://github.com/matrix-org/synapse/issues/16031))
+- Fix a long-standing bug where the `synapse_port_db` failed to configure sequences for application services and partial stated rooms. ([\#16043](https://github.com/matrix-org/synapse/issues/16043))
+- Fix deletion in dehydrated devices v2. ([\#16046](https://github.com/matrix-org/synapse/issues/16046))
+
+### Updates to the Docker image
+
+- Add `org.opencontainers.image.version` labels to Docker containers [published by Matrix.org](https://hub.docker.com/r/matrixdotorg/synapse). Contributed by Mo Balaa. ([\#15972](https://github.com/matrix-org/synapse/issues/15972), [\#16009](https://github.com/matrix-org/synapse/issues/16009))
+
+### Improved Documentation
+
+- Add a internal documentation page describing the ["streams" used within Synapse](https://matrix-org.github.io/synapse/v1.90/development/synapse_architecture/streams.html). ([\#16015](https://github.com/matrix-org/synapse/issues/16015))
+- Clarify comment on the keys/upload over replication enpoint. ([\#16016](https://github.com/matrix-org/synapse/issues/16016))
+- Do not expose Admin API in caddy reverse proxy example. Contributed by @NilsIrl. ([\#16027](https://github.com/matrix-org/synapse/issues/16027))
+
+### Deprecations and Removals
+
+- Remove support for legacy application service paths. ([\#15964](https://github.com/matrix-org/synapse/issues/15964))
+- Move support for application service query parameter authorization behind a configuration option. ([\#16017](https://github.com/matrix-org/synapse/issues/16017))
+
+### Internal Changes
+
+- Update SQL queries to inline boolean parameters as supported in SQLite 3.27. ([\#15525](https://github.com/matrix-org/synapse/issues/15525))
+- Allow for the configuration of the backoff algorithm for federation destinations. ([\#15754](https://github.com/matrix-org/synapse/issues/15754))
+- Allow modules to check whether the current worker is configured to run background tasks. ([\#15991](https://github.com/matrix-org/synapse/issues/15991))
+- Update support for [MSC3958](https://github.com/matrix-org/matrix-spec-proposals/pull/3958) to match the latest revision of the MSC. ([\#15992](https://github.com/matrix-org/synapse/issues/15992))
+- Allow modules to schedule delayed background calls. ([\#15993](https://github.com/matrix-org/synapse/issues/15993))
+- Update PyYAML to 6.0.1. ([\#16011](https://github.com/matrix-org/synapse/issues/16011))
+- Properly overwrite the `redacts` content-property for forwards-compatibility with room versions 1 through 10. ([\#16013](https://github.com/matrix-org/synapse/issues/16013))
+- Fix building the nix development environment on MacOS systems. ([\#16019](https://github.com/matrix-org/synapse/issues/16019))
+- Combine duplicated code. ([\#16023](https://github.com/matrix-org/synapse/issues/16023))
+- Collect additional metrics from `ResponseCache` for eviction. ([\#16028](https://github.com/matrix-org/synapse/issues/16028))
+- Update certifi to 2023.7.22 and pygments to 2.15.1. ([\#16044](https://github.com/matrix-org/synapse/issues/16044))
+- Fix endpoint improperly declaring support for MSC3814. ([\#16068](https://github.com/matrix-org/synapse/issues/16068))
+- Drop backwards compat hack for event serialization. ([\#16069](https://github.com/matrix-org/synapse/issues/16069))
+
+### Updates to locked dependencies
+
+* Bump cryptography from 41.0.2 to 41.0.3. ([\#16048](https://github.com/matrix-org/synapse/issues/16048))
+* Bump furo from 2023.5.20 to 2023.7.26. ([\#16077](https://github.com/matrix-org/synapse/issues/16077))
+* Bump immutabledict from 2.2.4 to 3.0.0. ([\#16034](https://github.com/matrix-org/synapse/issues/16034))
+* Bump jsonschema from 4.18.3 to 4.19.0. ([\#16081](https://github.com/matrix-org/synapse/issues/16081))
+* Bump phonenumbers from 8.13.14 to 8.13.18. ([\#16076](https://github.com/matrix-org/synapse/issues/16076))
+* Bump regex from 1.9.1 to 1.9.3. ([\#16073](https://github.com/matrix-org/synapse/issues/16073))
+* Bump serde from 1.0.171 to 1.0.175. ([\#15982](https://github.com/matrix-org/synapse/issues/15982))
+* Bump serde from 1.0.175 to 1.0.179. ([\#16033](https://github.com/matrix-org/synapse/issues/16033))
+* Bump serde from 1.0.179 to 1.0.183. ([\#16074](https://github.com/matrix-org/synapse/issues/16074))
+* Bump serde_json from 1.0.103 to 1.0.104. ([\#16032](https://github.com/matrix-org/synapse/issues/16032))
+* Bump service-identity from 21.1.0 to 23.1.0. ([\#16038](https://github.com/matrix-org/synapse/issues/16038))
+* Bump types-commonmark from 0.9.2.3 to 0.9.2.4. ([\#16037](https://github.com/matrix-org/synapse/issues/16037))
+* Bump types-jsonschema from 4.17.0.8 to 4.17.0.10. ([\#16036](https://github.com/matrix-org/synapse/issues/16036))
+* Bump types-netaddr from 0.8.0.8 to 0.8.0.9. ([\#16035](https://github.com/matrix-org/synapse/issues/16035))
+* Bump types-opentracing from 2.4.10.5 to 2.4.10.6. ([\#16078](https://github.com/matrix-org/synapse/issues/16078))
+* Bump types-setuptools from 68.0.0.0 to 68.0.0.3. ([\#16079](https://github.com/matrix-org/synapse/issues/16079))
+
 # Synapse 1.89.0 (2023-08-01)
 
 No significant changes since 1.89.0rc1.
diff --git a/changelog.d/15525.misc b/changelog.d/15525.misc
deleted file mode 100644
index 67ab0cf62..000000000
--- a/changelog.d/15525.misc
+++ /dev/null
@@ -1 +0,0 @@
-Update SQL queries to inline boolean parameters as supported in SQLite 3.27.
diff --git a/changelog.d/15629.feature b/changelog.d/15629.feature
deleted file mode 100644
index 16264effc..000000000
--- a/changelog.d/15629.feature
+++ /dev/null
@@ -1 +0,0 @@
-Scope transaction IDs to devices (implement [MSC3970](https://github.com/matrix-org/matrix-spec-proposals/pull/3970)).
diff --git a/changelog.d/15754.misc b/changelog.d/15754.misc
deleted file mode 100644
index 4314d415a..000000000
--- a/changelog.d/15754.misc
+++ /dev/null
@@ -1 +0,0 @@
-Allow for the configuration of the backoff algorithm for federation destinations.
diff --git a/changelog.d/15791.bugfix b/changelog.d/15791.bugfix
deleted file mode 100644
index 182634b62..000000000
--- a/changelog.d/15791.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix bug where purging history and paginating simultaneously could lead to database corruption when using workers.
diff --git a/changelog.d/15868.feature b/changelog.d/15868.feature
deleted file mode 100644
index a866bf577..000000000
--- a/changelog.d/15868.feature
+++ /dev/null
@@ -1 +0,0 @@
-Remove old rows from the `cache_invalidation_stream_by_instance` table automatically (this table is unused in SQLite).
diff --git a/changelog.d/15964.removal b/changelog.d/15964.removal
deleted file mode 100644
index 7613afe50..000000000
--- a/changelog.d/15964.removal
+++ /dev/null
@@ -1 +0,0 @@
-Remove support for legacy application service paths.
diff --git a/changelog.d/15972.docker b/changelog.d/15972.docker
deleted file mode 100644
index 7fd9707de..000000000
--- a/changelog.d/15972.docker
+++ /dev/null
@@ -1 +0,0 @@
-Add `org.opencontainers.image.version` labels to Docker containers [published by Matrix.org](https://hub.docker.com/r/matrixdotorg/synapse). Contributed by Mo Balaa.
diff --git a/changelog.d/15991.misc b/changelog.d/15991.misc
deleted file mode 100644
index 18f388cff..000000000
--- a/changelog.d/15991.misc
+++ /dev/null
@@ -1 +0,0 @@
-Allow modules to check whether the current worker is configured to run background tasks.
\ No newline at end of file
diff --git a/changelog.d/15992.misc b/changelog.d/15992.misc
deleted file mode 100644
index 539f55b47..000000000
--- a/changelog.d/15992.misc
+++ /dev/null
@@ -1 +0,0 @@
-Update support for [MSC3958](https://github.com/matrix-org/matrix-spec-proposals/pull/3958) to match the latest revision of the MSC.
diff --git a/changelog.d/15993.misc b/changelog.d/15993.misc
deleted file mode 100644
index 35ead0515..000000000
--- a/changelog.d/15993.misc
+++ /dev/null
@@ -1 +0,0 @@
-Allow modules to schedule delayed background calls.
\ No newline at end of file
diff --git a/changelog.d/16009.docker b/changelog.d/16009.docker
deleted file mode 100644
index 7fd9707de..000000000
--- a/changelog.d/16009.docker
+++ /dev/null
@@ -1 +0,0 @@
-Add `org.opencontainers.image.version` labels to Docker containers [published by Matrix.org](https://hub.docker.com/r/matrixdotorg/synapse). Contributed by Mo Balaa.
diff --git a/changelog.d/16011.misc b/changelog.d/16011.misc
deleted file mode 100644
index 8a8d9822c..000000000
--- a/changelog.d/16011.misc
+++ /dev/null
@@ -1 +0,0 @@
-Update PyYAML to 6.0.1.
diff --git a/changelog.d/16012.bugfix b/changelog.d/16012.bugfix
deleted file mode 100644
index 44ca9377f..000000000
--- a/changelog.d/16012.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix 404 not found code returned on profile endpoint when the display name is empty but not the avatar URL.
diff --git a/changelog.d/16013.misc b/changelog.d/16013.misc
deleted file mode 100644
index bd161e13e..000000000
--- a/changelog.d/16013.misc
+++ /dev/null
@@ -1 +0,0 @@
-Properly overwrite the `redacts` content-property for forwards-compatibility with room versions 1 through 10.
diff --git a/changelog.d/16015.doc b/changelog.d/16015.doc
deleted file mode 100644
index 1113d00dc..000000000
--- a/changelog.d/16015.doc
+++ /dev/null
@@ -1 +0,0 @@
-Add a internal documentation page describing the ["streams" used within Synapse](https://matrix-org.github.io/synapse/v1.90/development/synapse_architecture/streams.html).
diff --git a/changelog.d/16016.doc b/changelog.d/16016.doc
deleted file mode 100644
index e677058c2..000000000
--- a/changelog.d/16016.doc
+++ /dev/null
@@ -1,2 +0,0 @@
-Clarify comment on the keys/upload over replication enpoint.
-
diff --git a/changelog.d/16017.removal b/changelog.d/16017.removal
deleted file mode 100644
index 6b7244289..000000000
--- a/changelog.d/16017.removal
+++ /dev/null
@@ -1 +0,0 @@
-Move support for application service query parameter authorization behind a configuration option.
diff --git a/changelog.d/16019.misc b/changelog.d/16019.misc
deleted file mode 100644
index 0e583302e..000000000
--- a/changelog.d/16019.misc
+++ /dev/null
@@ -1 +0,0 @@
-Fix building the nix development environment on MacOS systems.
\ No newline at end of file
diff --git a/changelog.d/16023.misc b/changelog.d/16023.misc
deleted file mode 100644
index ee732318e..000000000
--- a/changelog.d/16023.misc
+++ /dev/null
@@ -1 +0,0 @@
-Combine duplicated code.
diff --git a/changelog.d/16027.doc b/changelog.d/16027.doc
deleted file mode 100644
index 201e88d6b..000000000
--- a/changelog.d/16027.doc
+++ /dev/null
@@ -1 +0,0 @@
-Do not expose Admin API in caddy reverse proxy example. Contributed by @NilsIrl.
diff --git a/changelog.d/16028.misc b/changelog.d/16028.misc
deleted file mode 100644
index 3a1e9fef0..000000000
--- a/changelog.d/16028.misc
+++ /dev/null
@@ -1 +0,0 @@
-Collect additional metrics from `ResponseCache` for eviction.
diff --git a/changelog.d/16031.bugfix b/changelog.d/16031.bugfix
deleted file mode 100644
index e48bf3975..000000000
--- a/changelog.d/16031.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Remove leading and trailing spaces when setting a display name.
diff --git a/changelog.d/16043.bugfix b/changelog.d/16043.bugfix
deleted file mode 100644
index 78c0f3455..000000000
--- a/changelog.d/16043.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix a long-standing bug where the `synapse_port_db` failed to configure sequences for application services and partial stated rooms.
diff --git a/changelog.d/16044.misc b/changelog.d/16044.misc
deleted file mode 100644
index 2e7137ccc..000000000
--- a/changelog.d/16044.misc
+++ /dev/null
@@ -1 +0,0 @@
-Update certifi to 2023.7.22 and pygments to 2.15.1.
diff --git a/changelog.d/16046.bugfix b/changelog.d/16046.bugfix
deleted file mode 100644
index ce5a9ae4b..000000000
--- a/changelog.d/16046.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix deletion in dehydrated devices v2.
diff --git a/changelog.d/16068.misc b/changelog.d/16068.misc
deleted file mode 100644
index 341426a74..000000000
--- a/changelog.d/16068.misc
+++ /dev/null
@@ -1 +0,0 @@
-Fix endpoint improperly declaring support for MSC3814.
diff --git a/changelog.d/16069.misc b/changelog.d/16069.misc
deleted file mode 100644
index f59ead863..000000000
--- a/changelog.d/16069.misc
+++ /dev/null
@@ -1 +0,0 @@
-Drop backwards compat hack for event serialization.
diff --git a/debian/changelog b/debian/changelog
index 90240b808..ed35abc9e 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+matrix-synapse-py3 (1.90.0~rc1) stable; urgency=medium
+
+  * New Synapse release 1.90.0rc1.
+
+ -- Synapse Packaging team <packages@matrix.org>  Tue, 08 Aug 2023 15:29:34 +0100
+
 matrix-synapse-py3 (1.89.0) stable; urgency=medium
 
   * New Synapse release 1.89.0.
diff --git a/pyproject.toml b/pyproject.toml
index 8304d2522..ca532e2c7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -89,7 +89,7 @@ manifest-path = "rust/Cargo.toml"
 
 [tool.poetry]
 name = "matrix-synapse"
-version = "1.89.0"
+version = "1.90.0rc1"
 description = "Homeserver for the Matrix decentralised comms protocol"
 authors = ["Matrix.org Team and Contributors <packages@matrix.org>"]
 license = "Apache-2.0"