diff --git a/config/hosts/matrix/matrix-synapse.nix b/config/hosts/matrix/matrix-synapse.nix
index dd92a5c..cd78f55 100644
--- a/config/hosts/matrix/matrix-synapse.nix
+++ b/config/hosts/matrix/matrix-synapse.nix
@@ -41,6 +41,8 @@
       max_upload_size = "500M";
 
       admin_contact = "mailto:yuri+ccchh@nekover.se";
+
+      default_room_version = "12";
     };
 
     extraConfigFiles = [