diff --git a/packages/backend/src/core/entities/UserEntityService.ts b/packages/backend/src/core/entities/UserEntityService.ts
index 47fc98f4790b..a47b3d51ac2b 100644
--- a/packages/backend/src/core/entities/UserEntityService.ts
+++ b/packages/backend/src/core/entities/UserEntityService.ts
@@ -452,6 +452,7 @@ export class UserEntityService implements OnModuleInit {
 				hasPendingReceivedFollowRequest: this.getHasPendingReceivedFollowRequest(user.id),
 				mutedWords: profile!.mutedWords,
 				mutedInstances: profile!.mutedInstances,
+				mutingNotificationTypes: [], // 後方互換性のため
 				notificationRecieveConfig: profile!.notificationRecieveConfig,
 				emailNotificationTypes: profile!.emailNotificationTypes,
 				achievements: profile!.achievements,