diff --git a/etc/matrix-synapse/conf.d/retention.yaml b/etc/matrix-synapse/conf.d/retention.yaml
index ae10feb..1d68d90 100644
--- a/etc/matrix-synapse/conf.d/retention.yaml
+++ b/etc/matrix-synapse/conf.d/retention.yaml
@@ -2,5 +2,6 @@ retention:
   enabled: false
 
 redaction_retention_period: 30d
+forgotten_room_retention_period: 7d
 user_ips_max_age: 60d
 delete_stale_devices_after: 120d