diff --git a/CHANGES.md b/CHANGES.md
index f4114acb60..c99b57a883 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,12 @@
+# Synapse 1.164.2 (2026-11-02)
+
+## Bugfixes
+
+- Restore the unstable [MSC2965](https://github.com/matrix-org/matrix-spec-proposals/pull/2965) `/auth_metadata` endpoint, which Element X clients still request after upgrading from Synapse 1.162 or earlier, causing them to fail to refresh their access token. ([\#20460](https://github.com/element-hq/synapse/issues/20460))
+
+
+
+
 # Synapse 1.164.1 (2026-10-28)
 
 ## Bugfixes
diff --git a/debian/changelog b/debian/changelog
index 8be78124a8..117f0b575f 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+matrix-synapse-py3 (1.164.2) stable; urgency=medium
+
+  * New synapse release 1.164.2.
+
+ -- Synapse Packaging team <packages@matrix.org>  Mon, 02 Nov 2026 15:59:43 +0000
+
 matrix-synapse-py3 (1.164.1) stable; urgency=medium
 
   * New synapse release 1.164.1.
diff --git a/pyproject.toml b/pyproject.toml
index 3826a88fcb..7850db8048 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "matrix-synapse"
-version = "1.164.1"
+version = "1.164.2"
 description = "Homeserver for the Matrix decentralised comms protocol"
 readme = "README.rst"
 authors = [
diff --git a/synapse/rest/client/auth_metadata.py b/synapse/rest/client/auth_metadata.py
index d8f172d0bd..a6b8c19502 100644
--- a/synapse/rest/client/auth_metadata.py
+++ b/synapse/rest/client/auth_metadata.py
@@ -30,11 +30,22 @@ class AuthMetadataServlet(RestServlet):
     Advertises the OAuth 2.0 server metadata for the homeserver.
     """
 
-    PATTERNS = client_patterns(
-        "/auth_metadata$",
-        releases=("v1",),
-        unstable=False,
-    )
+    # The unstable path is still requested by matrix-rust-sdk clients that last saw
+    # `/versions` before we advertised Matrix v1.15, and can be removed once those
+    # clients no longer get stuck on it.
+    # See https://github.com/element-hq/synapse/issues/20459
+    PATTERNS = [
+        *client_patterns(
+            "/auth_metadata$",
+            releases=("v1",),
+            unstable=False,
+        ),
+        *client_patterns(
+            "/org.matrix.msc2965/auth_metadata$",
+            releases=(),
+            unstable=True,
+        ),
+    ]
 
     def __init__(self, hs: "HomeServer"):
         super().__init__()
diff --git a/tests/rest/client/test_auth_metadata.py b/tests/rest/client/test_auth_metadata.py
index 57fe16241d..0e1310f74c 100644
--- a/tests/rest/client/test_auth_metadata.py
+++ b/tests/rest/client/test_auth_metadata.py
@@ -21,6 +21,8 @@ from http import HTTPStatus
 from typing import ClassVar
 from unittest.mock import Mock
 
+from parameterized import parameterized_class
+
 from twisted.internet.testing import MemoryReactor
 
 from synapse.api.auth.mas import MasDelegatedAuth
@@ -32,6 +34,13 @@ from synapse.util.clock import Clock
 from tests.unittest import HomeserverTestCase
 
 
+@parameterized_class(
+    ("endpoint",),
+    [
+        ("/_matrix/client/unstable/org.matrix.msc2965/auth_metadata",),
+        ("/_matrix/client/v1/auth_metadata",),
+    ],
+)
 class AuthMetadataMasDisabledTestCase(HomeserverTestCase):
     endpoint: ClassVar[str]
     servlets = [
@@ -40,11 +49,19 @@ class AuthMetadataMasDisabledTestCase(HomeserverTestCase):
 
     def test_returns_404_when_mas_disabled(self) -> None:
         # Make an unauthenticated request for the discovery info.
-        channel = self.make_request("GET", "/_matrix/client/v1/auth_metadata")
+        channel = self.make_request("GET", self.endpoint)
         self.assertEqual(channel.code, HTTPStatus.NOT_FOUND)
 
 
+@parameterized_class(
+    ("endpoint",),
+    [
+        ("/_matrix/client/unstable/org.matrix.msc2965/auth_metadata",),
+        ("/_matrix/client/v1/auth_metadata",),
+    ],
+)
 class AuthMetadataMasEnabledTestCase(HomeserverTestCase):
+    endpoint: ClassVar[str]
     servlets = [
         auth_metadata.register_servlets,
     ]
@@ -72,7 +89,7 @@ class AuthMetadataMasEnabledTestCase(HomeserverTestCase):
 
         self.auth.auth_metadata.return_value = test_auth_metadata
 
-        channel = self.make_request("GET", "/_matrix/client/v1/auth_metadata")
+        channel = self.make_request("GET", self.endpoint)
 
         self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
         self.assertEqual(channel.json_body, test_auth_metadata)