diff --git a/CHANGES.md b/CHANGES.md
index 2ef27f6ade..7b124d8a40 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,14 @@
+# Synapse 1.121.1 (2024-12-11)
+
+This release contains a fix for our docker build CI. It is functionally identical to 1.121.0, whose changelog is below.
+
+### Internal Changes
+
+- Downgrade the Ubuntu GHA runner when building docker images. ([\#18026](https://github.com/element-hq/synapse/issues/18026))
+
+
+
+
 # Synapse 1.121.0 (2024-12-11)
 
 This release contains the security fixes from [v1.120.2](https://github.com/element-hq/synapse/releases/tag/v1.120.2).
diff --git a/changelog.d/18026.misc b/changelog.d/18026.misc
deleted file mode 100644
index 729f72c4a2..0000000000
--- a/changelog.d/18026.misc
+++ /dev/null
@@ -1 +0,0 @@
-Downgrade the Ubuntu GHA runner when building docker images.
diff --git a/debian/changelog b/debian/changelog
index 8149cd7486..fc34d8ac3f 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+matrix-synapse-py3 (1.121.1) stable; urgency=medium
+
+  * New Synapse release 1.121.1.
+
+ -- Synapse Packaging team <packages@matrix.org>  Wed, 11 Dec 2024 18:24:48 +0000
+
 matrix-synapse-py3 (1.121.0) stable; urgency=medium
 
   * New Synapse release 1.121.0.
diff --git a/pyproject.toml b/pyproject.toml
index a8a86b4d5c..0430371586 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -97,7 +97,7 @@ module-name = "synapse.synapse_rust"
 
 [tool.poetry]
 name = "matrix-synapse"
-version = "1.121.0"
+version = "1.121.1"
 description = "Homeserver for the Matrix decentralised comms protocol"
 authors = ["Matrix.org Team and Contributors <packages@matrix.org>"]
 license = "AGPL-3.0-or-later"