diff --git a/CHANGES.md b/CHANGES.md
index 62ea684e5..b04abbeb4 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,24 @@
+Synapse 1.40.0rc3 (2021-08-09)
+==============================
+
+Features
+--------
+
+- Support [MSC3289: room version 8](https://github.com/matrix-org/matrix-doc/pull/3289). ([\#10449](https://github.com/matrix-org/synapse/issues/10449))
+
+
+Bugfixes
+--------
+
+- Mark the experimental room version from [MSC2716](https://github.com/matrix-org/matrix-doc/pull/2716) as unstable. ([\#10449](https://github.com/matrix-org/synapse/issues/10449))
+
+
+Improved Documentation
+----------------------
+
+- Fix broken links in `upgrade.md`. Contributed by @dklimpel. ([\#10543](https://github.com/matrix-org/synapse/issues/10543))
+
+
 Synapse 1.40.0rc2 (2021-08-04)
 ==============================
 
diff --git a/changelog.d/10449.bugfix b/changelog.d/10449.bugfix
deleted file mode 100644
index c5e23ba01..000000000
--- a/changelog.d/10449.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Mark the experimental room version from [MSC2716](https://github.com/matrix-org/matrix-doc/pull/2716) as unstable.
diff --git a/changelog.d/10449.feature b/changelog.d/10449.feature
deleted file mode 100644
index a45a17cb2..000000000
--- a/changelog.d/10449.feature
+++ /dev/null
@@ -1 +0,0 @@
-Support [MSC3289: room version 8](https://github.com/matrix-org/matrix-doc/pull/3289).
diff --git a/changelog.d/10543.doc b/changelog.d/10543.doc
deleted file mode 100644
index 6c06722eb..000000000
--- a/changelog.d/10543.doc
+++ /dev/null
@@ -1 +0,0 @@
-Fix broken links in `upgrade.md`. Contributed by @dklimpel.
diff --git a/debian/changelog b/debian/changelog
index c523101f9..7b44341bc 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+matrix-synapse-py3 (1.40.0~rc3) stable; urgency=medium
+
+  * New synapse release 1.40.0~rc3.
+
+ -- Synapse Packaging team <packages@matrix.org>  Mon, 09 Aug 2021 13:41:08 +0100
+
 matrix-synapse-py3 (1.40.0~rc2) stable; urgency=medium
 
   * New synapse release 1.40.0~rc2.
diff --git a/synapse/__init__.py b/synapse/__init__.py
index da5246353..5cca899f7 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -47,7 +47,7 @@ try:
 except ImportError:
     pass
 
-__version__ = "1.40.0rc2"
+__version__ = "1.40.0rc3"
 
 if bool(os.environ.get("SYNAPSE_TEST_PATCH_LOG_CONTEXTS", False)):
     # We import here so that we don't have to install a bunch of deps when