diff --git a/changelog.d/10448.feature b/changelog.d/10448.feature
new file mode 100644
index 000000000000..a45a17cb28fd
--- /dev/null
+++ b/changelog.d/10448.feature
@@ -0,0 +1 @@
+Support [MSC3289: room version 8](https://github.com/matrix-org/matrix-doc/pull/3289).
diff --git a/synapse/api/room_versions.py b/synapse/api/room_versions.py
index 697319e52dc5..7cc7ace75675 100644
--- a/synapse/api/room_versions.py
+++ b/synapse/api/room_versions.py
@@ -193,6 +193,19 @@ class RoomVersions:
         msc3083_join_rules=False,
         msc2403_knocking=True,
     )
+    V8 = RoomVersion(
+        "8",
+        RoomDisposition.STABLE,
+        EventFormatVersions.V3,
+        StateResolutionVersions.V2,
+        enforce_key_validity=True,
+        special_case_aliases_auth=False,
+        strict_canonicaljson=True,
+        limit_notifications_power_levels=True,
+        msc2176_redaction_rules=False,
+        msc3083_join_rules=True,
+        msc2403_knocking=True,
+    )
 
 
 KNOWN_ROOM_VERSIONS: Dict[str, RoomVersion] = {
@@ -207,6 +220,7 @@ class RoomVersions:
         RoomVersions.MSC2176,
         RoomVersions.MSC3083,
         RoomVersions.V7,
+        RoomVersions.V8,
     )
 }
 
@@ -234,12 +248,12 @@ class RoomVersionCapability:
     for cap in (
         RoomVersionCapability(
             "knock",
-            RoomVersions.V7,
+            RoomVersions.V8,
             lambda room_version: room_version.msc2403_knocking,
         ),
         RoomVersionCapability(
             "restricted",
-            None,
+            RoomVersions.V8,
             lambda room_version: room_version.msc3083_join_rules,
         ),
     )