diff --git a/.changeset/cyan-pots-appear.md b/.changeset/cyan-pots-appear.md
new file mode 100644
index 0000000000..f82f4548c3
--- /dev/null
+++ b/.changeset/cyan-pots-appear.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-catalog-backend-module-unprocessed': minor
+---
+
+**BREAKING** Removed support for the legacy backend and removed references to `@backstage/backend-common`, please [migrate to the new backend system](https://backstage.io/docs/backend-system/building-plugins-and-modules/migrating)
diff --git a/packages/backend-legacy/package.json b/packages/backend-legacy/package.json
index a5a05f05ac..eef3fc1bb5 100644
--- a/packages/backend-legacy/package.json
+++ b/packages/backend-legacy/package.json
@@ -38,7 +38,6 @@
     "@backstage/plugin-auth-node": "workspace:^",
     "@backstage/plugin-catalog-backend": "workspace:^",
     "@backstage/plugin-catalog-backend-module-scaffolder-entity-model": "workspace:^",
-    "@backstage/plugin-catalog-backend-module-unprocessed": "workspace:^",
     "@backstage/plugin-catalog-node": "workspace:^",
     "@backstage/plugin-events-backend": "workspace:^",
     "@backstage/plugin-events-node": "workspace:^",
diff --git a/packages/backend-legacy/src/plugins/catalog.ts b/packages/backend-legacy/src/plugins/catalog.ts
index c83d5844d1..022b9de4e6 100644
--- a/packages/backend-legacy/src/plugins/catalog.ts
+++ b/packages/backend-legacy/src/plugins/catalog.ts
@@ -16,7 +16,6 @@
 
 import { CatalogBuilder } from '@backstage/plugin-catalog-backend';
 import { ScaffolderEntitiesProcessor } from '@backstage/plugin-catalog-backend-module-scaffolder-entity-model';
-import { UnprocessedEntitiesModule } from '@backstage/plugin-catalog-backend-module-unprocessed';
 import { Router } from 'express';
 import { PluginEnvironment } from '../types';
 import { DemoEventBasedEntityProvider } from './DemoEventBasedEntityProvider';
@@ -37,15 +36,6 @@ export default async function createPlugin(
 
   const { processingEngine, router } = await builder.build();
 
-  const unprocessed = UnprocessedEntitiesModule.create({
-    database: await env.database.getClient(),
-    router,
-    permissions: env.permissions,
-    discovery: env.discovery,
-  });
-
-  unprocessed.registerRoutes();
-
   await processingEngine.start();
   return router;
 }
diff --git a/plugins/catalog-backend-module-unprocessed/README.md b/plugins/catalog-backend-module-unprocessed/README.md
index f01347912d..21ab19ca72 100644
--- a/plugins/catalog-backend-module-unprocessed/README.md
+++ b/plugins/catalog-backend-module-unprocessed/README.md
@@ -19,19 +19,3 @@ In `packages/backend/src/index.ts` add the module:
 ```ts title="packages/backend/src/index.ts"
 backend.add(import('@backstage/plugin-catalog-backend-module-unprocessed'));
 ```
-
-### Legacy Backend
-
-In `packages/backend/src/plugins/catalog.ts` import the module and initialize it after invoking `CatalogBuilder.build()`:
-
-```ts title="packages/backend/src/plugins/catalog.ts"
-import { UnprocessedEntitiesModule } from '@backstage/plugin-catalog-backend-module-unprocessed';
-
-//...
-
-const unprocessed = new UnprocessedEntitiesModule(
-  await env.database.getClient(),
-  router,
-);
-unprocessed.registerRoutes();
-```
diff --git a/plugins/catalog-backend-module-unprocessed/package.json b/plugins/catalog-backend-module-unprocessed/package.json
index 290c314760..88d4d6c3ae 100644
--- a/plugins/catalog-backend-module-unprocessed/package.json
+++ b/plugins/catalog-backend-module-unprocessed/package.json
@@ -33,7 +33,6 @@
     "test": "backstage-cli package test"
   },
   "dependencies": {
-    "@backstage/backend-common": "^0.25.0",
     "@backstage/backend-plugin-api": "workspace:^",
     "@backstage/catalog-model": "workspace:^",
     "@backstage/errors": "workspace:^",
diff --git a/plugins/catalog-backend-module-unprocessed/report.api.md b/plugins/catalog-backend-module-unprocessed/report.api.md
index 493082ac7c..85ddc0e3ac 100644
--- a/plugins/catalog-backend-module-unprocessed/report.api.md
+++ b/plugins/catalog-backend-module-unprocessed/report.api.md
@@ -4,27 +4,8 @@
 
 ```ts
 import { BackendFeature } from '@backstage/backend-plugin-api';
-import { DiscoveryService } from '@backstage/backend-plugin-api';
-import { HttpAuthService } from '@backstage/backend-plugin-api';
-import { HttpRouterService } from '@backstage/backend-plugin-api';
-import { Knex } from 'knex';
-import { PermissionsService } from '@backstage/backend-plugin-api';
 
 // @public
 const catalogModuleUnprocessedEntities: BackendFeature;
 export default catalogModuleUnprocessedEntities;
-
-// @public
-export class UnprocessedEntitiesModule {
-  // (undocumented)
-  static create(options: {
-    router: Pick<HttpRouterService, 'use'>;
-    database: Knex;
-    discovery: DiscoveryService;
-    permissions: PermissionsService;
-    httpAuth?: HttpAuthService;
-  }): UnprocessedEntitiesModule;
-  // (undocumented)
-  registerRoutes(): void;
-}
 ```
diff --git a/plugins/catalog-backend-module-unprocessed/src/UnprocessedEntitiesModule.ts b/plugins/catalog-backend-module-unprocessed/src/UnprocessedEntitiesModule.ts
index 34aedd61af..ce25ba2bd1 100644
--- a/plugins/catalog-backend-module-unprocessed/src/UnprocessedEntitiesModule.ts
+++ b/plugins/catalog-backend-module-unprocessed/src/UnprocessedEntitiesModule.ts
@@ -22,7 +22,6 @@ import {
 } from './types';
 import { Knex } from 'knex';
 import {
-  DiscoveryService,
   HttpAuthService,
   HttpRouterService,
   PermissionsService,
@@ -36,12 +35,11 @@ import {
 } from '@backstage/plugin-permission-common';
 import { unprocessedEntitiesDeletePermission } from '@backstage/plugin-catalog-unprocessed-entities-common';
 import { NotAllowedError } from '@backstage/errors';
-import { createLegacyAuthAdapters } from '@backstage/backend-common';
 
 /**
  * Module providing Unprocessed Entities API endpoints
  *
- * @public
+ * @internal
  */
 export class UnprocessedEntitiesModule {
   private readonly moduleRouter;
@@ -52,30 +50,24 @@ export class UnprocessedEntitiesModule {
     private readonly database: Knex,
     private readonly router: Pick<HttpRouterService, 'use'>,
     private readonly permissions: PermissionsService,
-    discovery: DiscoveryService,
-    httpAuth?: HttpAuthService,
+    httpAuth: HttpAuthService,
   ) {
     this.moduleRouter = Router();
     this.router.use(this.moduleRouter);
 
-    this.httpAuth = createLegacyAuthAdapters({
-      discovery,
-      httpAuth,
-    }).httpAuth;
+    this.httpAuth = httpAuth;
   }
 
   static create(options: {
     router: Pick<HttpRouterService, 'use'>;
     database: Knex;
-    discovery: DiscoveryService;
     permissions: PermissionsService;
-    httpAuth?: HttpAuthService;
+    httpAuth: HttpAuthService;
   }) {
     return new UnprocessedEntitiesModule(
       options.database,
       options.router,
       options.permissions,
-      options.discovery,
       options.httpAuth,
     );
   }
diff --git a/plugins/catalog-backend-module-unprocessed/src/index.ts b/plugins/catalog-backend-module-unprocessed/src/index.ts
index 20132d9b27..912d69d8c0 100644
--- a/plugins/catalog-backend-module-unprocessed/src/index.ts
+++ b/plugins/catalog-backend-module-unprocessed/src/index.ts
@@ -21,4 +21,3 @@
  */
 
 export { catalogModuleUnprocessedEntities as default } from './module';
-export * from './UnprocessedEntitiesModule';
diff --git a/plugins/catalog-backend-module-unprocessed/src/module.ts b/plugins/catalog-backend-module-unprocessed/src/module.ts
index bf1d50a634..1b46cb4448 100644
--- a/plugins/catalog-backend-module-unprocessed/src/module.ts
+++ b/plugins/catalog-backend-module-unprocessed/src/module.ts
@@ -36,7 +36,6 @@ export const catalogModuleUnprocessedEntities = createBackendModule({
         router: coreServices.httpRouter,
         logger: coreServices.logger,
         httpAuth: coreServices.httpAuth,
-        discovery: coreServices.discovery,
         permissions: coreServices.permissions,
         permissionsRegistry: coreServices.permissionsRegistry,
       },
@@ -46,14 +45,12 @@ export const catalogModuleUnprocessedEntities = createBackendModule({
         logger,
         permissions,
         httpAuth,
-        discovery,
         permissionsRegistry,
       }) {
         const module = UnprocessedEntitiesModule.create({
           database: await database.getClient(),
           router,
           permissions,
-          discovery,
           httpAuth,
         });
 
diff --git a/yarn.lock b/yarn.lock
index 810ff12c31..b07e6c1367 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5784,7 +5784,6 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "@backstage/plugin-catalog-backend-module-unprocessed@workspace:plugins/catalog-backend-module-unprocessed"
   dependencies:
-    "@backstage/backend-common": "npm:^0.25.0"
     "@backstage/backend-plugin-api": "workspace:^"
     "@backstage/catalog-model": "workspace:^"
     "@backstage/cli": "workspace:^"
@@ -28965,7 +28964,6 @@ __metadata:
     "@backstage/plugin-auth-node": "workspace:^"
     "@backstage/plugin-catalog-backend": "workspace:^"
     "@backstage/plugin-catalog-backend-module-scaffolder-entity-model": "workspace:^"
-    "@backstage/plugin-catalog-backend-module-unprocessed": "workspace:^"
     "@backstage/plugin-catalog-node": "workspace:^"
     "@backstage/plugin-events-backend": "workspace:^"
     "@backstage/plugin-events-node": "workspace:^"