diff --git a/.changeset/dry-hounds-study.md b/.changeset/dry-hounds-study.md
new file mode 100644
index 0000000000..0d58431439
--- /dev/null
+++ b/.changeset/dry-hounds-study.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-signals-backend': minor
+---
+
+Removed support for the old backend system. If you were using the old `createRouter` export, please migrate to [the new backend system](https://backstage.io/docs/backend-system/).
diff --git a/packages/backend-legacy/src/index.ts b/packages/backend-legacy/src/index.ts
index 8ef969ff2b..c883603efb 100644
--- a/packages/backend-legacy/src/index.ts
+++ b/packages/backend-legacy/src/index.ts
@@ -47,7 +47,6 @@ import search from './plugins/search';
 import techdocs from './plugins/techdocs';
 import app from './plugins/app';
 import permission from './plugins/permission';
-import signals from './plugins/signals';
 import { PluginEnvironment } from './types';
 import { ServerPermissionClient } from '@backstage/plugin-permission-node';
 import { DefaultIdentityClient } from '@backstage/plugin-auth-node';
@@ -137,7 +136,6 @@ async function main() {
   const appEnv = useHotMemoize(module, () => createEnv('app'));
   const permissionEnv = useHotMemoize(module, () => createEnv('permission'));
   const eventsEnv = useHotMemoize(module, () => createEnv('events'));
-  const signalsEnv = useHotMemoize(module, () => createEnv('signals'));
 
   const apiRouter = Router();
   apiRouter.use('/catalog', await catalog(catalogEnv));
@@ -149,7 +147,6 @@ async function main() {
   apiRouter.use('/kubernetes', await kubernetes(kubernetesEnv));
   apiRouter.use('/proxy', await proxy(proxyEnv));
   apiRouter.use('/permission', await permission(permissionEnv));
-  apiRouter.use('/signals', await signals(signalsEnv));
   apiRouter.use(notFoundHandler());
 
   const service = createServiceBuilder(module)
diff --git a/packages/backend-legacy/src/plugins/signals.ts b/packages/backend-legacy/src/plugins/signals.ts
deleted file mode 100644
index 33b1af5edf..0000000000
--- a/packages/backend-legacy/src/plugins/signals.ts
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- * Copyright 2023 The Backstage Authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-import { Router } from 'express';
-import { createRouter } from '@backstage/plugin-signals-backend';
-import { PluginEnvironment } from '../types';
-
-export default async function createPlugin(
-  env: PluginEnvironment,
-): Promise<Router> {
-  return await createRouter({
-    logger: env.logger,
-    events: env.events,
-    identity: env.identity,
-    discovery: env.discovery,
-    config: env.config,
-  });
-}
diff --git a/plugins/signals-backend/package.json b/plugins/signals-backend/package.json
index 9a10b0e43b..8f26a4dea8 100644
--- a/plugins/signals-backend/package.json
+++ b/plugins/signals-backend/package.json
@@ -37,14 +37,12 @@
     "test": "backstage-cli package test"
   },
   "dependencies": {
-    "@backstage/backend-common": "^0.25.0",
     "@backstage/backend-plugin-api": "workspace:^",
     "@backstage/config": "workspace:^",
     "@backstage/plugin-auth-node": "workspace:^",
     "@backstage/plugin-events-node": "workspace:^",
     "@backstage/plugin-signals-node": "workspace:^",
     "@backstage/types": "workspace:^",
-    "@types/express": "^4.17.6",
     "express": "^4.17.1",
     "express-promise-router": "^4.1.0",
     "http-proxy-middleware": "^2.0.0",
@@ -60,6 +58,7 @@
     "@backstage/plugin-auth-backend": "workspace:^",
     "@backstage/plugin-auth-backend-module-guest-provider": "workspace:^",
     "@backstage/plugin-events-backend": "workspace:^",
+    "@types/express": "^4.17.6",
     "@types/supertest": "^2.0.8",
     "@types/ws": "^8.5.10",
     "msw": "^1.0.0",
diff --git a/plugins/signals-backend/report.api.md b/plugins/signals-backend/report.api.md
index 10f74ba37e..2b27ef2b3c 100644
--- a/plugins/signals-backend/report.api.md
+++ b/plugins/signals-backend/report.api.md
@@ -3,39 +3,7 @@
 > Do not edit this file. It is a report generated by [API Extractor](https://api-extractor.com/).
 
 ```ts
-import { AuthService } from '@backstage/backend-plugin-api';
 import { BackendFeature } from '@backstage/backend-plugin-api';
-import { Config } from '@backstage/config';
-import { DiscoveryService } from '@backstage/backend-plugin-api';
-import { EventsService } from '@backstage/plugin-events-node';
-import express from 'express';
-import { IdentityApi } from '@backstage/plugin-auth-node';
-import { LifecycleService } from '@backstage/backend-plugin-api';
-import { LoggerService } from '@backstage/backend-plugin-api';
-import { UserInfoService } from '@backstage/backend-plugin-api';
-
-// @public @deprecated (undocumented)
-export function createRouter(options: RouterOptions): Promise<express.Router>;
-
-// @public @deprecated (undocumented)
-export interface RouterOptions {
-  // (undocumented)
-  auth?: AuthService;
-  // (undocumented)
-  config: Config;
-  // (undocumented)
-  discovery: DiscoveryService;
-  // (undocumented)
-  events: EventsService;
-  // (undocumented)
-  identity?: IdentityApi;
-  // (undocumented)
-  lifecycle?: LifecycleService;
-  // (undocumented)
-  logger: LoggerService;
-  // (undocumented)
-  userInfo?: UserInfoService;
-}
 
 // @public
 const signalsPlugin: BackendFeature;
diff --git a/plugins/signals-backend/src/deprecated.ts b/plugins/signals-backend/src/deprecated.ts
deleted file mode 100644
index d33c9a06b9..0000000000
--- a/plugins/signals-backend/src/deprecated.ts
+++ /dev/null
@@ -1,60 +0,0 @@
-/*
- * Copyright 2024 The Backstage Authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-import express from 'express';
-
-import { Config } from '@backstage/config';
-import {
-  AuthService,
-  DiscoveryService,
-  LifecycleService,
-  LoggerService,
-  UserInfoService,
-} from '@backstage/backend-plugin-api';
-import { createLegacyAuthAdapters } from '@backstage/backend-common';
-
-import { IdentityApi } from '@backstage/plugin-auth-node';
-import { EventsService } from '@backstage/plugin-events-node';
-
-import { createRouter as _createRouter } from './service/router';
-
-/**
- * @public
- * @deprecated Please migrate to the new backend system as this will be removed in the future.
- */
-export interface RouterOptions {
-  logger: LoggerService;
-  events: EventsService;
-  identity?: IdentityApi;
-  discovery: DiscoveryService;
-  config: Config;
-  lifecycle?: LifecycleService;
-  auth?: AuthService;
-  userInfo?: UserInfoService;
-}
-
-/**
- * @public
- * @deprecated Please migrate to the new backend system as this will be removed in the future.
- */
-export async function createRouter(
-  options: RouterOptions,
-): Promise<express.Router> {
-  return _createRouter({
-    ...options,
-    ...createLegacyAuthAdapters(options),
-  });
-}
diff --git a/plugins/signals-backend/src/index.ts b/plugins/signals-backend/src/index.ts
index c852c81518..c5b3fe692a 100644
--- a/plugins/signals-backend/src/index.ts
+++ b/plugins/signals-backend/src/index.ts
@@ -14,5 +14,4 @@
  * limitations under the License.
  */
 
-export * from './deprecated';
 export { signalsPlugin as default } from './plugin';
diff --git a/plugins/signals-backend/src/plugin.ts b/plugins/signals-backend/src/plugin.ts
index 3ca10f46d1..f01777b4fc 100644
--- a/plugins/signals-backend/src/plugin.ts
+++ b/plugins/signals-backend/src/plugin.ts
@@ -13,12 +13,13 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 import {
   coreServices,
   createBackendPlugin,
 } from '@backstage/backend-plugin-api';
-import { createRouter } from './deprecated';
 import { eventsServiceRef } from '@backstage/plugin-events-node';
+import { createRouter } from './service/router';
 
 /**
  * Signals backend plugin
diff --git a/plugins/signals-backend/src/service/SignalManager.test.ts b/plugins/signals-backend/src/service/SignalManager.test.ts
index eccc715d1b..642c00a7d7 100644
--- a/plugins/signals-backend/src/service/SignalManager.test.ts
+++ b/plugins/signals-backend/src/service/SignalManager.test.ts
@@ -13,10 +13,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 import { WebSocket } from 'ws';
 import { EventsServiceSubscribeOptions } from '@backstage/plugin-events-node';
 import { SignalManager } from './SignalManager';
-import { ConfigReader } from '@backstage/config';
 import { mockServices } from '@backstage/backend-test-utils';
 
 class MockWebSocket {
@@ -70,15 +70,15 @@ describe('SignalManager', () => {
   };
 
   const shutdownHooks: Function[] = [];
-  const mockLifecycle = {
+  const mockLifecycle = mockServices.lifecycle.mock({
     addShutdownHook: (hook: Function) => shutdownHooks.push(hook),
-  };
+  });
 
   const manager = SignalManager.create({
     events: mockEvents,
     logger: mockServices.logger.mock(),
-    config: new ConfigReader({}),
-    lifecycle: mockLifecycle as any,
+    config: mockServices.rootConfig(),
+    lifecycle: mockLifecycle,
   });
 
   it('should close all connections when server is closed', () => {
diff --git a/plugins/signals-backend/src/service/SignalManager.ts b/plugins/signals-backend/src/service/SignalManager.ts
index bf20d6a8c4..ec9cb57900 100644
--- a/plugins/signals-backend/src/service/SignalManager.ts
+++ b/plugins/signals-backend/src/service/SignalManager.ts
@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 import { EventParams, EventsService } from '@backstage/plugin-events-node';
 import { SignalPayload } from '@backstage/plugin-signals-node';
 import crypto from 'crypto';
@@ -45,7 +46,7 @@ export type SignalManagerOptions = {
   events: EventsService;
   config: Config;
   logger: LoggerService;
-  lifecycle?: LifecycleService;
+  lifecycle: LifecycleService;
 };
 
 /** @internal */
@@ -79,7 +80,7 @@ export class SignalManager {
         this.onEventBrokerEvent(params.eventPayload as SignalPayload),
     });
 
-    options.lifecycle?.addShutdownHook(() => this.onShutdown());
+    options.lifecycle.addShutdownHook(() => this.onShutdown());
   }
 
   private ping() {
diff --git a/plugins/signals-backend/src/service/router.test.ts b/plugins/signals-backend/src/service/router.test.ts
index acc49739b8..0138a1a5d3 100644
--- a/plugins/signals-backend/src/service/router.test.ts
+++ b/plugins/signals-backend/src/service/router.test.ts
@@ -16,9 +16,7 @@
 
 import express from 'express';
 import request from 'supertest';
-
 import { createRouter } from './router';
-import { ConfigReader } from '@backstage/config';
 import { mockErrorHandler, mockServices } from '@backstage/backend-test-utils';
 
 const eventsServiceMock = mockServices.events.mock();
@@ -36,7 +34,8 @@ describe('createRouter', () => {
       events: eventsServiceMock,
       discovery,
       userInfo,
-      config: new ConfigReader({}),
+      config: mockServices.rootConfig(),
+      lifecycle: mockServices.lifecycle.mock(),
       auth: mockServices.auth(),
     });
     app = express().use(router).use(mockErrorHandler());
diff --git a/plugins/signals-backend/src/service/router.ts b/plugins/signals-backend/src/service/router.ts
index 0633e5fb8d..eb1c24f383 100644
--- a/plugins/signals-backend/src/service/router.ts
+++ b/plugins/signals-backend/src/service/router.ts
@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 import express, { NextFunction, Request, Response } from 'express';
 import Router from 'express-promise-router';
 import {
@@ -36,7 +37,7 @@ export interface RouterOptions {
   events: EventsService;
   discovery: DiscoveryService;
   config: Config;
-  lifecycle?: LifecycleService;
+  lifecycle: LifecycleService;
   userInfo: UserInfoService;
   auth: AuthService;
 }
diff --git a/yarn.lock b/yarn.lock
index e7583ddd90..66f1511bd6 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -7928,7 +7928,6 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "@backstage/plugin-signals-backend@workspace:plugins/signals-backend"
   dependencies:
-    "@backstage/backend-common": ^0.25.0
     "@backstage/backend-defaults": "workspace:^"
     "@backstage/backend-plugin-api": "workspace:^"
     "@backstage/backend-test-utils": "workspace:^"