diff --git a/src/api/client_server/unversioned.rs b/src/api/client_server/unversioned.rs
index 49cb7bf5..f1b35a20 100644
--- a/src/api/client_server/unversioned.rs
+++ b/src/api/client_server/unversioned.rs
@@ -37,6 +37,7 @@ pub async fn get_supported_versions_route(
         unstable_features: BTreeMap::from_iter([
             ("org.matrix.e2e_cross_signing".to_owned(), true),
             ("org.matrix.msc2836".to_owned(), true),
+            ("org.matrix.msc3827".to_owned(), true),
             ("org.matrix.msc2946".to_owned(), true),
         ]),
     };