diff --git a/CHANGES.md b/CHANGES.md
index bc0d4fe8c8853544abfc0543bef7ef6e68373f0b..fcb50cd8c23b2a098d7610d4b4203a11afcbda67 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -2,6 +2,70 @@
 
 ### Features
 
+- Implements an admin API to lock an user without deactivating them. Based on [MSC3939](https://github.com/matrix-org/matrix-spec-proposals/pull/3939). ([\#15870](https://github.com/matrix-org/synapse/issues/15870))
+- Implements a task scheduler for	resumable potentially long running tasks. ([\#15891](https://github.com/matrix-org/synapse/issues/15891))
+- Allow specifying `client_secret_path` as alternative to `client_secret` for OIDC providers. This avoids leaking the client secret in the homeserver config. Contributed by @Ma27. ([\#16030](https://github.com/matrix-org/synapse/issues/16030))
+- Allow customising the IdP display name, icon, and brand for SAML and CAS providers (in addition to OIDC provider). ([\#16094](https://github.com/matrix-org/synapse/issues/16094))
+- Add an `admins` query parameter to the [List Accounts](https://matrix-org.github.io/synapse/v1.91/admin_api/user_admin_api.html#list-accounts) [admin API](https://matrix-org.github.io/synapse/v1.91/usage/administration/admin_api/index.html), to include only admins or to exclude admins in user queries. ([\#16114](https://github.com/matrix-org/synapse/issues/16114))
+
+### Bugfixes
+
+- Fix long-standing bug where concurrent requests to change a user's push rules could cause a deadlock. Contributed by Nick @ Beeper (@fizzadar). ([\#16052](https://github.com/matrix-org/synapse/issues/16052))
+- Fix a long-standing bu in `/sync` where timeout=0 does not skip caching, resulting in slow calls in cases where there are no new changes. Contributed by @PlasmaIntec. ([\#16080](https://github.com/matrix-org/synapse/issues/16080))
+- Fix performance of state resolutions for large, old rooms that did not have the full auth chain persisted. ([\#16116](https://github.com/matrix-org/synapse/issues/16116))
+- Filter out user agent references to the sliding sync proxy and rust-sdk from the user_daily_visits table to ensure that Element X can be represented fully. ([\#16124](https://github.com/matrix-org/synapse/issues/16124))
+- User constent and 3-PID changes capability cannot be enabled when using experimental [MSC3861](https://github.com/matrix-org/matrix-spec-proposals/pull/3861) support. ([\#16127](https://github.com/matrix-org/synapse/issues/16127), [\#16134](https://github.com/matrix-org/synapse/issues/16134))
+- Fix a rare race that could block new events from being sent for up to two minutes. Introduced in v1.90.0. ([\#16133](https://github.com/matrix-org/synapse/issues/16133), [\#16169](https://github.com/matrix-org/synapse/issues/16169))
+- Fix performance degredation when there are a lot of in-flight replication requests. ([\#16148](https://github.com/matrix-org/synapse/issues/16148))
+- Fix a bug introduced in 1.87 where synapse would send an excessive amount of federation requests to servers which have been offline for a long time. Contributed by Nico. ([\#16156](https://github.com/matrix-org/synapse/issues/16156), [\#16164](https://github.com/matrix-org/synapse/issues/16164))
+
+### Improved Documentation
+
+- Structured logging docs: add a link to explain the ELK stack ([\#16091](https://github.com/matrix-org/synapse/issues/16091))
+
+### Internal Changes
+
+- Update dehydrated devices implementation. ([\#16010](https://github.com/matrix-org/synapse/issues/16010))
+- Fix database performance of read/write worker locks. ([\#16061](https://github.com/matrix-org/synapse/issues/16061))
+- Fix building the nix development environment on MacOS systems. ([\#16063](https://github.com/matrix-org/synapse/issues/16063))
+- Override global statement timeout when creating indexes in Postgres. ([\#16085](https://github.com/matrix-org/synapse/issues/16085))
+- Fix the type annotation on `run_db_interaction` in the Module API. ([\#16089](https://github.com/matrix-org/synapse/issues/16089))
+- Clean-up the presence code. ([\#16092](https://github.com/matrix-org/synapse/issues/16092))
+- Run `pyupgrade` for Python 3.8+. ([\#16110](https://github.com/matrix-org/synapse/issues/16110))
+- Rename pagination and purge locks and add comments to explain why they exist and how they work. ([\#16112](https://github.com/matrix-org/synapse/issues/16112))
+- Attempt to fix the twisted trunk job. ([\#16115](https://github.com/matrix-org/synapse/issues/16115))
+- Cache token introspection response from OIDC provider. ([\#16117](https://github.com/matrix-org/synapse/issues/16117))
+- Add cache to `get_server_keys_json_for_remote`. ([\#16123](https://github.com/matrix-org/synapse/issues/16123))
+- Add an admin endpoint to allow authorizing server to signal token revocations. ([\#16125](https://github.com/matrix-org/synapse/issues/16125))
+- Add response time metrics for introspection requests for delegated auth. ([\#16131](https://github.com/matrix-org/synapse/issues/16131))
+- MSC3861: allow impersonation by an admin user using `_oidc_admin_impersonate_user_id` query parameter. ([\#16132](https://github.com/matrix-org/synapse/issues/16132))
+- Increase performance of read/write locks. ([\#16149](https://github.com/matrix-org/synapse/issues/16149))
+- Improve presence tests. ([\#16150](https://github.com/matrix-org/synapse/issues/16150), [\#16151](https://github.com/matrix-org/synapse/issues/16151), [\#16158](https://github.com/matrix-org/synapse/issues/16158))
+- Raised the poetry-core version cap to 1.7.0. ([\#16152](https://github.com/matrix-org/synapse/issues/16152))
+- Fix assertion in user directory unit tests. ([\#16157](https://github.com/matrix-org/synapse/issues/16157))
+- Reduce scope of locks when paginating to alleviate DB contention. ([\#16159](https://github.com/matrix-org/synapse/issues/16159))
+- Reduce DB contention on worker locks. ([\#16160](https://github.com/matrix-org/synapse/issues/16160))
+- Task scheduler: mark task as active if we are scheduling as soon as possible. ([\#16165](https://github.com/matrix-org/synapse/issues/16165))
+
+### Updates to locked dependencies
+
+* Bump click from 8.1.6 to 8.1.7. ([\#16145](https://github.com/matrix-org/synapse/issues/16145))
+* Bump gitpython from 3.1.31 to 3.1.32. ([\#16103](https://github.com/matrix-org/synapse/issues/16103))
+* Bump ijson from 3.2.1 to 3.2.3. ([\#16143](https://github.com/matrix-org/synapse/issues/16143))
+* Bump isort from 5.11.5 to 5.12.0. ([\#16108](https://github.com/matrix-org/synapse/issues/16108))
+* Bump log from 0.4.19 to 0.4.20. ([\#16109](https://github.com/matrix-org/synapse/issues/16109))
+* Bump pygithub from 1.59.0 to 1.59.1. ([\#16144](https://github.com/matrix-org/synapse/issues/16144))
+* Bump sentry-sdk from 1.28.1 to 1.29.2. ([\#16142](https://github.com/matrix-org/synapse/issues/16142))
+* Bump serde from 1.0.183 to 1.0.184. ([\#16139](https://github.com/matrix-org/synapse/issues/16139))
+* Bump txredisapi from 1.4.9 to 1.4.10. ([\#16107](https://github.com/matrix-org/synapse/issues/16107))
+* Bump types-bleach from 6.0.0.3 to 6.0.0.4. ([\#16106](https://github.com/matrix-org/synapse/issues/16106))
+* Bump types-pillow from 10.0.0.1 to 10.0.0.2. ([\#16105](https://github.com/matrix-org/synapse/issues/16105))
+* Bump types-pyopenssl from 23.2.0.1 to 23.2.0.2. ([\#16146](https://github.com/matrix-org/synapse/issues/16146))
+
+# Synapse 1.91.0rc1 (2023-08-23)
+
+### Features
+
 - Implements an admin API to lock an user without deactivating them. Based on [MSC3939](https://github.com/matrix-org/matrix-spec-proposals/pull/3939). ([\#15870](https://github.com/matrix-org/synapse/issues/15870))
 - Allow specifying `client_secret_path` as alternative to `client_secret` for OIDC providers. This avoids leaking the client secret in the homeserver config. Contributed by @Ma27. ([\#16030](https://github.com/matrix-org/synapse/issues/16030))
 - Allow customising the IdP display name, icon, and brand for SAML and CAS providers (in addition to OIDC provider). ([\#16094](https://github.com/matrix-org/synapse/issues/16094))
diff --git a/changelog.d/15870.feature b/changelog.d/15870.feature
deleted file mode 100644
index 527220d637d8bb094255e98cb491daf44a11bf20..0000000000000000000000000000000000000000
--- a/changelog.d/15870.feature
+++ /dev/null
@@ -1 +0,0 @@
-Implements an admin API to lock an user without deactivating them. Based on [MSC3939](https://github.com/matrix-org/matrix-spec-proposals/pull/3939).
diff --git a/changelog.d/15891.feature b/changelog.d/15891.feature
deleted file mode 100644
index 5024b5adc435b119ce70853b58cabf0b484d8037..0000000000000000000000000000000000000000
--- a/changelog.d/15891.feature
+++ /dev/null
@@ -1 +0,0 @@
-Implements a task scheduler for	resumable potentially long running tasks.
diff --git a/changelog.d/16010.misc b/changelog.d/16010.misc
deleted file mode 100644
index 1e1a1480691058a7731885e16f2a1aa529a62e83..0000000000000000000000000000000000000000
--- a/changelog.d/16010.misc
+++ /dev/null
@@ -1 +0,0 @@
-Update dehydrated devices implementation.
diff --git a/changelog.d/16030.feature b/changelog.d/16030.feature
deleted file mode 100644
index c2f068085f1d8acdee6e414b0bfd5fbb8cc73dca..0000000000000000000000000000000000000000
--- a/changelog.d/16030.feature
+++ /dev/null
@@ -1 +0,0 @@
-Allow specifying `client_secret_path` as alternative to `client_secret` for OIDC providers. This avoids leaking the client secret in the homeserver config. Contributed by @Ma27.
diff --git a/changelog.d/16052.bugfix b/changelog.d/16052.bugfix
deleted file mode 100644
index 3c7a60f226a742b69599dd18b458765cff6d0843..0000000000000000000000000000000000000000
--- a/changelog.d/16052.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix long-standing bug where concurrent requests to change a user's push rules could cause a deadlock. Contributed by Nick @ Beeper (@fizzadar).
diff --git a/changelog.d/16061.misc b/changelog.d/16061.misc
deleted file mode 100644
index 37928b670f1e0a1c99c6e442726025e61f9934d8..0000000000000000000000000000000000000000
--- a/changelog.d/16061.misc
+++ /dev/null
@@ -1 +0,0 @@
-Fix database performance of read/write worker locks.
diff --git a/changelog.d/16063.misc b/changelog.d/16063.misc
deleted file mode 100644
index 069fc1adaba06a4d2f3002dfeb9fcbdd26f9618f..0000000000000000000000000000000000000000
--- a/changelog.d/16063.misc
+++ /dev/null
@@ -1 +0,0 @@
-Fix building the nix development environment on MacOS systems.
diff --git a/changelog.d/16080.bugfix b/changelog.d/16080.bugfix
deleted file mode 100644
index 1ad6fb3c52054f475a08b2a3e54fce1ced34aed7..0000000000000000000000000000000000000000
--- a/changelog.d/16080.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix a long-standing bu in `/sync` where timeout=0 does not skip caching, resulting in slow calls in cases where there are no new changes. Contributed by @PlasmaIntec.
\ No newline at end of file
diff --git a/changelog.d/16085.misc b/changelog.d/16085.misc
deleted file mode 100644
index 7b7a95edd4f91f5f1b43918c273534dc0c3bba56..0000000000000000000000000000000000000000
--- a/changelog.d/16085.misc
+++ /dev/null
@@ -1 +0,0 @@
-Override global statement timeout when creating indexes in Postgres.
diff --git a/changelog.d/16089.misc b/changelog.d/16089.misc
deleted file mode 100644
index 8c302e6884d16dec199c599e1623323f4e1b336f..0000000000000000000000000000000000000000
--- a/changelog.d/16089.misc
+++ /dev/null
@@ -1 +0,0 @@
-Fix the type annotation on `run_db_interaction` in the Module API.
\ No newline at end of file
diff --git a/changelog.d/16091.doc b/changelog.d/16091.doc
deleted file mode 100644
index a043df4efd8ddb6733cbff69e6cc849b3abf40c0..0000000000000000000000000000000000000000
--- a/changelog.d/16091.doc
+++ /dev/null
@@ -1 +0,0 @@
-Structured logging docs: add a link to explain the ELK stack
diff --git a/changelog.d/16092.misc b/changelog.d/16092.misc
deleted file mode 100644
index b52080777105d686747d46fbe3c508ebc434ed5a..0000000000000000000000000000000000000000
--- a/changelog.d/16092.misc
+++ /dev/null
@@ -1 +0,0 @@
-Clean-up the presence code.
diff --git a/changelog.d/16094.feature b/changelog.d/16094.feature
deleted file mode 100644
index 3be71badb9826a1479bc636c47025ac66c71dd5d..0000000000000000000000000000000000000000
--- a/changelog.d/16094.feature
+++ /dev/null
@@ -1 +0,0 @@
-Allow customising the IdP display name, icon, and brand for SAML and CAS providers (in addition to OIDC provider).
diff --git a/changelog.d/16110.misc b/changelog.d/16110.misc
deleted file mode 100644
index 68efe86ddc68877001c43884a11d3ba6c96363cd..0000000000000000000000000000000000000000
--- a/changelog.d/16110.misc
+++ /dev/null
@@ -1 +0,0 @@
-Run `pyupgrade` for Python 3.8+.
diff --git a/changelog.d/16112.misc b/changelog.d/16112.misc
deleted file mode 100644
index 05a58c1348a8f0d021bc660f3acca8a911e87ea1..0000000000000000000000000000000000000000
--- a/changelog.d/16112.misc
+++ /dev/null
@@ -1 +0,0 @@
-Rename pagination and purge locks and add comments to explain why they exist and how they work.
diff --git a/changelog.d/16114.feature b/changelog.d/16114.feature
deleted file mode 100644
index e937a3b029fe3bced1eac5514aa6b1acbdc38850..0000000000000000000000000000000000000000
--- a/changelog.d/16114.feature
+++ /dev/null
@@ -1 +0,0 @@
-Add an `admins` query parameter to the [List Accounts](https://matrix-org.github.io/synapse/v1.91/admin_api/user_admin_api.html#list-accounts) [admin API](https://matrix-org.github.io/synapse/v1.91/usage/administration/admin_api/index.html), to include only admins or to exclude admins in user queries.
\ No newline at end of file
diff --git a/changelog.d/16115.misc b/changelog.d/16115.misc
deleted file mode 100644
index f325d2a31dbd113599fb647302730ee6503ff7cc..0000000000000000000000000000000000000000
--- a/changelog.d/16115.misc
+++ /dev/null
@@ -1 +0,0 @@
-Attempt to fix the twisted trunk job.
diff --git a/changelog.d/16116.bugfix b/changelog.d/16116.bugfix
deleted file mode 100644
index f57a26ae398885bb883d82cda173b6c7f6c79e3b..0000000000000000000000000000000000000000
--- a/changelog.d/16116.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix performance of state resolutions for large, old rooms that did not have the full auth chain persisted.
diff --git a/changelog.d/16117.misc b/changelog.d/16117.misc
deleted file mode 100644
index f33fa6dc1751626ce86d97819bbe45088103c4a8..0000000000000000000000000000000000000000
--- a/changelog.d/16117.misc
+++ /dev/null
@@ -1 +0,0 @@
-Cache token introspection response from OIDC provider.
diff --git a/changelog.d/16123.misc b/changelog.d/16123.misc
deleted file mode 100644
index b7c6b7c2f20133f00e4f84901766a21ce48d128d..0000000000000000000000000000000000000000
--- a/changelog.d/16123.misc
+++ /dev/null
@@ -1 +0,0 @@
-Add cache to `get_server_keys_json_for_remote`.
diff --git a/changelog.d/16124.bugfix b/changelog.d/16124.bugfix
deleted file mode 100644
index fb1d501a2fac605f6f99d609313493a11c374480..0000000000000000000000000000000000000000
--- a/changelog.d/16124.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Filter out user agent references to the sliding sync proxy and rust-sdk from the user_daily_visits table to ensure that Element X can be represented fully.
diff --git a/changelog.d/16125.misc b/changelog.d/16125.misc
deleted file mode 100644
index 2f1bf23108293f4cc3ac61f8c8faf400dcd250ef..0000000000000000000000000000000000000000
--- a/changelog.d/16125.misc
+++ /dev/null
@@ -1 +0,0 @@
-Add an admin endpoint to allow authorizing server to signal token revocations.
diff --git a/changelog.d/16127.bugfix b/changelog.d/16127.bugfix
deleted file mode 100644
index 9ce5f4a705f7efd3d4d4564ced1f82426de12b5b..0000000000000000000000000000000000000000
--- a/changelog.d/16127.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-User constent and 3-PID changes capability cannot be enabled when using experimental [MSC3861](https://github.com/matrix-org/matrix-spec-proposals/pull/3861) support.
diff --git a/changelog.d/16131.misc b/changelog.d/16131.misc
deleted file mode 100644
index 4f04699512f7aa9212c0cbe0eb3a17fa3a4aa9ab..0000000000000000000000000000000000000000
--- a/changelog.d/16131.misc
+++ /dev/null
@@ -1 +0,0 @@
-Add response time metrics for introspection requests for delegated auth.
diff --git a/changelog.d/16132.misc b/changelog.d/16132.misc
deleted file mode 100644
index aca26079d8f115465483a8fa99f48599a04a9041..0000000000000000000000000000000000000000
--- a/changelog.d/16132.misc
+++ /dev/null
@@ -1 +0,0 @@
-MSC3861: allow impersonation by an admin user using `_oidc_admin_impersonate_user_id` query parameter.
diff --git a/changelog.d/16133.bugfix b/changelog.d/16133.bugfix
deleted file mode 100644
index ed8830692fe73f865ac698fe825692335851d970..0000000000000000000000000000000000000000
--- a/changelog.d/16133.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix a rare race that could block new events from being sent for up to two minutes. Introduced in v1.90.0.
diff --git a/changelog.d/16134.bugfix b/changelog.d/16134.bugfix
deleted file mode 100644
index 9ce5f4a705f7efd3d4d4564ced1f82426de12b5b..0000000000000000000000000000000000000000
--- a/changelog.d/16134.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-User constent and 3-PID changes capability cannot be enabled when using experimental [MSC3861](https://github.com/matrix-org/matrix-spec-proposals/pull/3861) support.
diff --git a/changelog.d/16148.bugfix b/changelog.d/16148.bugfix
deleted file mode 100644
index fea316f8562bd5570e93a0f70be5a6b98b56a84c..0000000000000000000000000000000000000000
--- a/changelog.d/16148.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix performance degredation when there are a lot of in-flight replication requests.
diff --git a/changelog.d/16149.misc b/changelog.d/16149.misc
deleted file mode 100644
index 8b6674d2aa26018c399c6cce7642af4754e3fbed..0000000000000000000000000000000000000000
--- a/changelog.d/16149.misc
+++ /dev/null
@@ -1 +0,0 @@
-Increase performance of read/write locks.
diff --git a/changelog.d/16150.misc b/changelog.d/16150.misc
deleted file mode 100644
index 41059378c52860632fe7fc07b32fc1f66020a99b..0000000000000000000000000000000000000000
--- a/changelog.d/16150.misc
+++ /dev/null
@@ -1 +0,0 @@
-Improve presence tests.
diff --git a/changelog.d/16151.misc b/changelog.d/16151.misc
deleted file mode 100644
index 41059378c52860632fe7fc07b32fc1f66020a99b..0000000000000000000000000000000000000000
--- a/changelog.d/16151.misc
+++ /dev/null
@@ -1 +0,0 @@
-Improve presence tests.
diff --git a/changelog.d/16152.misc b/changelog.d/16152.misc
deleted file mode 100644
index f8bf9f2c524825062a10f4a5c45cf51625680f43..0000000000000000000000000000000000000000
--- a/changelog.d/16152.misc
+++ /dev/null
@@ -1 +0,0 @@
-Raised the poetry-core version cap to 1.7.0.
diff --git a/changelog.d/16156.bugfix b/changelog.d/16156.bugfix
deleted file mode 100644
index 17284297cfaead7ee52bc2b78cb3992fbf941143..0000000000000000000000000000000000000000
--- a/changelog.d/16156.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix a bug introduced in 1.87 where synapse would send an excessive amount of federation requests to servers which have been offline for a long time. Contributed by Nico.
diff --git a/changelog.d/16157.misc b/changelog.d/16157.misc
deleted file mode 100644
index c9d8999cca1b6d77b6275f8e2b4c363668fc178a..0000000000000000000000000000000000000000
--- a/changelog.d/16157.misc
+++ /dev/null
@@ -1 +0,0 @@
-Fix assertion in user directory unit tests.
diff --git a/changelog.d/16158.misc b/changelog.d/16158.misc
deleted file mode 100644
index 41059378c52860632fe7fc07b32fc1f66020a99b..0000000000000000000000000000000000000000
--- a/changelog.d/16158.misc
+++ /dev/null
@@ -1 +0,0 @@
-Improve presence tests.
diff --git a/changelog.d/16159.misc b/changelog.d/16159.misc
deleted file mode 100644
index 04cdd1afafb6253ac67151bd904cf7bca6f6073c..0000000000000000000000000000000000000000
--- a/changelog.d/16159.misc
+++ /dev/null
@@ -1 +0,0 @@
-Reduce scope of locks when paginating to alleviate DB contention.
diff --git a/changelog.d/16160.misc b/changelog.d/16160.misc
deleted file mode 100644
index 78803b7bcd1e427906e4756936e649cac5299482..0000000000000000000000000000000000000000
--- a/changelog.d/16160.misc
+++ /dev/null
@@ -1 +0,0 @@
-Reduce DB contention on worker locks.
diff --git a/changelog.d/16164.bugfix b/changelog.d/16164.bugfix
deleted file mode 100644
index 17284297cfaead7ee52bc2b78cb3992fbf941143..0000000000000000000000000000000000000000
--- a/changelog.d/16164.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix a bug introduced in 1.87 where synapse would send an excessive amount of federation requests to servers which have been offline for a long time. Contributed by Nico.
diff --git a/changelog.d/16165.misc b/changelog.d/16165.misc
deleted file mode 100644
index b4d514d249cc65c71282a4e670df2ac792cb266e..0000000000000000000000000000000000000000
--- a/changelog.d/16165.misc
+++ /dev/null
@@ -1 +0,0 @@
-Task scheduler: mark task as active if we are scheduling as soon as possible.
diff --git a/changelog.d/16169.bugfix b/changelog.d/16169.bugfix
deleted file mode 100644
index ed8830692fe73f865ac698fe825692335851d970..0000000000000000000000000000000000000000
--- a/changelog.d/16169.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix a rare race that could block new events from being sent for up to two minutes. Introduced in v1.90.0.
diff --git a/debian/changelog b/debian/changelog
index ad9a4b3c8cfd5f6d78bfbae7715a4ef000eed75d..8b0615e4211748f53f3ea0abd222d7ddb3e8a16f 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+matrix-synapse-py3 (1.91.0~rc1) stable; urgency=medium
+
+  * New Synapse release 1.91.0rc1.
+
+ -- Synapse Packaging team <packages@matrix.org>  Wed, 23 Aug 2023 09:47:18 -0700
+
 matrix-synapse-py3 (1.90.0) stable; urgency=medium
 
   * New Synapse release 1.90.0.
diff --git a/pyproject.toml b/pyproject.toml
index 0585a9b01e95b49bd0f3fc77a6b727dccac2bb61..c2421d7257d78b340bc539e0cbe56f3ad8a47b9c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -89,7 +89,7 @@ manifest-path = "rust/Cargo.toml"
 
 [tool.poetry]
 name = "matrix-synapse"
-version = "1.90.0"
+version = "1.91.0rc1"
 description = "Homeserver for the Matrix decentralised comms protocol"
 authors = ["Matrix.org Team and Contributors <packages@matrix.org>"]
 license = "Apache-2.0"