diff --git a/fmo_server/schema/v9.sql b/fmo_server/schema/v9.sql
new file mode 100644
index 0000000..da99bc3
--- /dev/null
+++ b/fmo_server/schema/v9.sql
@@ -0,0 +1,11 @@
+-- Add missing index on nostr_federations(federation_id) that was omitted in v7
+BEGIN;
+
+CREATE INDEX IF NOT EXISTS nostr_federations_federation_id ON nostr_federations (federation_id);
+
+INSERT INTO
+    schema_version (version)
+VALUES
+    (9);
+
+COMMIT;
diff --git a/fmo_server/src/federation/observer.rs b/fmo_server/src/federation/observer.rs
index ae982f6..0d111eb 100644
--- a/fmo_server/src/federation/observer.rs
+++ b/fmo_server/src/federation/observer.rs
@@ -191,6 +191,7 @@ impl FederationObserver {
                 "/schema/v8.sql",
                 FederationObserver::backfill_reprocess_all_sessions
             ),
+            migration!("/schema/v9.sql"),
         ];
 
         for (index, migration) in migrations.iter().enumerate() {