diff --git a/.changeset/bright-moles-sort.md b/.changeset/bright-moles-sort.md
new file mode 100644
index 0000000000..9796729d1a
--- /dev/null
+++ b/.changeset/bright-moles-sort.md
@@ -0,0 +1,5 @@
+---
+'@backstage/backend-dynamic-feature-service': minor
+---
+
+**BREAKING** Removed support for the legacy backend, please migrate to the new backend system
diff --git a/.changeset/old-crews-serve.md b/.changeset/old-crews-serve.md
new file mode 100644
index 0000000000..8b588aeb50
--- /dev/null
+++ b/.changeset/old-crews-serve.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-catalog-backend-module-incremental-ingestion': minor
+---
+
+**BREAKING** Removed support for the legacy backend, please [migrate to the new backend system](https://github.com/backstage/backstage/tree/v1.38.0/plugins/catalog-backend-module-incremental-ingestion#installation).
diff --git a/packages/backend-dynamic-feature-service/report.api.md b/packages/backend-dynamic-feature-service/report.api.md
index 37701abd18..8aa1470e60 100644
--- a/packages/backend-dynamic-feature-service/report.api.md
+++ b/packages/backend-dynamic-feature-service/report.api.md
@@ -5,31 +5,15 @@
 ```ts
 import { BackendFeature } from '@backstage/backend-plugin-api';
 import { BackstagePackageJson } from '@backstage/cli-node';
-import { CatalogBuilder } from '@backstage/plugin-catalog-backend';
 import { Config } from '@backstage/config';
 import { ConfigSchema } from '@backstage/config-loader';
-import { DatabaseService } from '@backstage/backend-plugin-api';
-import { DiscoveryService } from '@backstage/backend-plugin-api';
-import { EventBroker } from '@backstage/plugin-events-node';
-import { EventsService } from '@backstage/plugin-events-node';
-import { HttpPostIngressOptions } from '@backstage/plugin-events-node';
-import { IdentityApi } from '@backstage/plugin-auth-node';
-import { IndexBuilder } from '@backstage/plugin-search-backend-node';
 import { JsonObject } from '@backstage/types';
-import { Logger } from 'winston';
 import { LoggerService } from '@backstage/backend-plugin-api';
 import { PackagePlatform } from '@backstage/cli-node';
 import { PackageRole } from '@backstage/cli-node';
-import { PermissionEvaluator } from '@backstage/plugin-permission-common';
-import { PermissionPolicy } from '@backstage/plugin-permission-node';
 import { RootLoggerService } from '@backstage/backend-plugin-api';
-import { Router } from 'express';
-import { SchedulerService } from '@backstage/backend-plugin-api';
-import { SchedulerServiceTaskRunner } from '@backstage/backend-plugin-api';
 import { ServiceFactory } from '@backstage/backend-plugin-api';
 import { ServiceRef } from '@backstage/backend-plugin-api';
-import { TemplateAction } from '@backstage/plugin-scaffolder-node';
-import { UrlReaderService } from '@backstage/backend-plugin-api';
 import { WinstonLoggerOptions } from '@backstage/backend-defaults/rootLogger';
 
 // @public (undocumented)
@@ -44,9 +28,7 @@ export interface BackendDynamicPlugin extends BaseDynamicPlugin {
 }
 
 // @public (undocumented)
-export type BackendDynamicPluginInstaller =
-  | LegacyBackendPluginInstaller
-  | NewBackendPluginInstaller;
+export type BackendDynamicPluginInstaller = NewBackendPluginInstaller;
 
 // @public (undocumented)
 export interface BackendPluginProvider {
@@ -271,48 +253,6 @@ export function isBackendDynamicPluginInstaller(
   obj: any,
 ): obj is BackendDynamicPluginInstaller;
 
-// @public @deprecated (undocumented)
-export interface LegacyBackendPluginInstaller {
-  // (undocumented)
-  catalog?(builder: CatalogBuilder, env: LegacyPluginEnvironment): void;
-  // (undocumented)
-  events?(env: LegacyPluginEnvironment): HttpPostIngressOptions[];
-  // (undocumented)
-  kind: 'legacy';
-  // (undocumented)
-  permissions?: {
-    policy?: PermissionPolicy;
-  };
-  // (undocumented)
-  router?: {
-    pluginID: string;
-    createPlugin(env: LegacyPluginEnvironment): Promise<Router>;
-  };
-  // (undocumented)
-  scaffolder?(env: LegacyPluginEnvironment): TemplateAction<any>[];
-  // (undocumented)
-  search?(
-    indexBuilder: IndexBuilder,
-    schedule: SchedulerServiceTaskRunner,
-    env: LegacyPluginEnvironment,
-  ): void;
-}
-
-// @public @deprecated (undocumented)
-export type LegacyPluginEnvironment = {
-  logger: Logger;
-  database: DatabaseService;
-  config: Config;
-  reader: UrlReaderService;
-  discovery: DiscoveryService;
-  permissions: PermissionEvaluator;
-  scheduler: SchedulerService;
-  identity: IdentityApi;
-  eventBroker: EventBroker;
-  events: EventsService;
-  pluginProvider: BackendPluginProvider;
-};
-
 // @public (undocumented)
 export interface ModuleLoader {
   // (undocumented)
diff --git a/packages/backend-dynamic-feature-service/src/manager/index.ts b/packages/backend-dynamic-feature-service/src/manager/index.ts
index 391ea46249..53c86d63c8 100644
--- a/packages/backend-dynamic-feature-service/src/manager/index.ts
+++ b/packages/backend-dynamic-feature-service/src/manager/index.ts
@@ -23,8 +23,6 @@ export type {
   BackendDynamicPlugin,
   BackendDynamicPluginInstaller,
   NewBackendPluginInstaller,
-  LegacyBackendPluginInstaller,
-  LegacyPluginEnvironment,
   DynamicPluginProvider,
   FrontendPluginProvider,
   BackendPluginProvider,
diff --git a/packages/backend-dynamic-feature-service/src/manager/plugin-manager.test.ts b/packages/backend-dynamic-feature-service/src/manager/plugin-manager.test.ts
index d7133a804a..8d8fd13151 100644
--- a/packages/backend-dynamic-feature-service/src/manager/plugin-manager.test.ts
+++ b/packages/backend-dynamic-feature-service/src/manager/plugin-manager.test.ts
@@ -30,13 +30,10 @@ import {
   BackendDynamicPlugin,
   BaseDynamicPlugin,
   DynamicPlugin,
-  LegacyBackendPluginInstaller,
   NewBackendPluginInstaller,
-  LegacyPluginEnvironment,
 } from './types';
 import { ScannedPluginManifest, ScannedPluginPackage } from '../scanner/types';
 import { randomUUID } from 'crypto';
-import { TemplateAction } from '@backstage/plugin-scaffolder-node';
 import { createSpecializedBackend } from '@backstage/backend-app-api';
 import { ConfigSources } from '@backstage/config-loader';
 import { Logs, MockedLogger, LogContent } from '../__testUtils__/testUtils';
@@ -552,49 +549,6 @@ describe('backend-dynamic-feature-service', () => {
           ]);
         },
       },
-      {
-        name: 'should successfully load a legacy backend plugin',
-        packageManifest: {
-          name: 'backend-dynamic-plugin-test',
-          version: '0.0.0',
-          backstage: {
-            role: 'backend-plugin',
-          },
-          main: 'dist/index.cjs.js',
-        },
-        indexFile: {
-          relativePath: ['dist', 'index.cjs.js'],
-          content:
-            'exports.dynamicPluginInstaller={ kind: "legacy", scaffolder: (env)=>[] }',
-        },
-        expectedLogs(location) {
-          return {
-            infos: [
-              {
-                message: `loaded dynamic backend plugin 'backend-dynamic-plugin-test' from '${location}'`,
-              },
-            ],
-          };
-        },
-        checkLoadedPlugins(plugins) {
-          expect(plugins).toMatchObject([
-            {
-              name: 'backend-dynamic-plugin-test',
-              version: '0.0.0',
-              role: 'backend-plugin',
-              platform: 'node',
-              installer: {
-                kind: 'legacy',
-              },
-            },
-          ]);
-          const installer = (plugins[0] as BackendDynamicPlugin)
-            .installer as LegacyBackendPluginInstaller;
-          expect(installer.scaffolder!({} as LegacyPluginEnvironment)).toEqual<
-            TemplateAction<any>[]
-          >([]);
-        },
-      },
       {
         name: 'should successfully load a frontend plugin',
         packageManifest: {
diff --git a/packages/backend-dynamic-feature-service/src/manager/types.ts b/packages/backend-dynamic-feature-service/src/manager/types.ts
index 165f13003a..6bbadbf992 100644
--- a/packages/backend-dynamic-feature-service/src/manager/types.ts
+++ b/packages/backend-dynamic-feature-service/src/manager/types.ts
@@ -14,58 +14,10 @@
  * limitations under the License.
  */
 
-import { Logger } from 'winston';
-import { Config } from '@backstage/config';
-import { Router } from 'express';
-import { IdentityApi } from '@backstage/plugin-auth-node';
-import { PermissionEvaluator } from '@backstage/plugin-permission-common';
-import {
-  EventBroker,
-  EventsService,
-  HttpPostIngressOptions,
-} from '@backstage/plugin-events-node';
-
-import {
-  BackendFeature,
-  UrlReaderService,
-  SchedulerService,
-  SchedulerServiceTaskRunner,
-  DatabaseService,
-  DiscoveryService,
-} from '@backstage/backend-plugin-api';
+import { BackendFeature } from '@backstage/backend-plugin-api';
 import { PackagePlatform, PackageRole } from '@backstage/cli-node';
-import { CatalogBuilder } from '@backstage/plugin-catalog-backend';
-import { TemplateAction } from '@backstage/plugin-scaffolder-node';
-import { IndexBuilder } from '@backstage/plugin-search-backend-node';
-import { PermissionPolicy } from '@backstage/plugin-permission-node';
 import { ScannedPluginPackage } from '../scanner';
 
-/**
- * @public
- *
- * @deprecated
- *
- * Support for the legacy backend system will be removed in the future.
- *
- * When adding a legacy plugin installer entrypoint in your plugin,
- * you should always take the opportunity to also implement support
- * for the new backend system if not already done.
- *
- */
-export type LegacyPluginEnvironment = {
-  logger: Logger;
-  database: DatabaseService;
-  config: Config;
-  reader: UrlReaderService;
-  discovery: DiscoveryService;
-  permissions: PermissionEvaluator;
-  scheduler: SchedulerService;
-  identity: IdentityApi;
-  eventBroker: EventBroker;
-  events: EventsService;
-  pluginProvider: BackendPluginProvider;
-};
-
 /**
  * @public
  */
@@ -126,9 +78,7 @@ export interface BackendDynamicPlugin extends BaseDynamicPlugin {
 /**
  * @public
  */
-export type BackendDynamicPluginInstaller =
-  | LegacyBackendPluginInstaller
-  | NewBackendPluginInstaller;
+export type BackendDynamicPluginInstaller = NewBackendPluginInstaller;
 
 /**
  * @public
@@ -139,38 +89,6 @@ export interface NewBackendPluginInstaller {
   install(): BackendFeature | BackendFeature[];
 }
 
-/**
- * @public
- * @deprecated
- *
- * Support for the legacy backend system will be removed in the future.
- *
- * When adding a legacy plugin installer entrypoint in your plugin,
- * you should always take the opportunity to also implement support
- * for the new backend system if not already done.
- *
- */
-export interface LegacyBackendPluginInstaller {
-  kind: 'legacy';
-
-  router?: {
-    pluginID: string;
-    createPlugin(env: LegacyPluginEnvironment): Promise<Router>;
-  };
-
-  catalog?(builder: CatalogBuilder, env: LegacyPluginEnvironment): void;
-  scaffolder?(env: LegacyPluginEnvironment): TemplateAction<any>[];
-  search?(
-    indexBuilder: IndexBuilder,
-    schedule: SchedulerServiceTaskRunner,
-    env: LegacyPluginEnvironment,
-  ): void;
-  events?(env: LegacyPluginEnvironment): HttpPostIngressOptions[];
-  permissions?: {
-    policy?: PermissionPolicy;
-  };
-}
-
 /**
  * @public
  */
diff --git a/plugins/catalog-backend-module-incremental-ingestion/report.api.md b/plugins/catalog-backend-module-incremental-ingestion/report.api.md
index df77a254c8..4c82b011b1 100644
--- a/plugins/catalog-backend-module-incremental-ingestion/report.api.md
+++ b/plugins/catalog-backend-module-incremental-ingestion/report.api.md
@@ -4,11 +4,9 @@
 
 ```ts
 import { BackendFeature } from '@backstage/backend-plugin-api';
-import { CatalogBuilder } from '@backstage/plugin-catalog-backend';
 import { DatabaseService } from '@backstage/backend-plugin-api';
 import type { DeferredEntity } from '@backstage/plugin-catalog-node';
 import { EventParams } from '@backstage/plugin-events-node';
-import { EventSubscriber } from '@backstage/plugin-events-node';
 import { ExtensionPoint } from '@backstage/backend-plugin-api';
 import { HumanDuration } from '@backstage/types';
 import { IncrementalEntityProvider as IncrementalEntityProvider_2 } from '@backstage/plugin-catalog-backend-module-incremental-ingestion';
@@ -16,7 +14,6 @@ import { IncrementalEntityProviderOptions as IncrementalEntityProviderOptions_2
 import { PermissionsService } from '@backstage/backend-plugin-api';
 import { RootConfigService } from '@backstage/backend-plugin-api';
 import { RootLoggerService } from '@backstage/backend-plugin-api';
-import { Router } from 'express';
 import { SchedulerService } from '@backstage/backend-plugin-api';
 import { UrlReaderService } from '@backstage/backend-plugin-api';
 
@@ -37,23 +34,6 @@ export type EntityIteratorResult<T> =
       cursor?: T;
     };
 
-// @public @deprecated (undocumented)
-export class IncrementalCatalogBuilder {
-  // (undocumented)
-  addIncrementalEntityProvider<TCursor, TContext>(
-    provider: IncrementalEntityProvider<TCursor, TContext>,
-    options: IncrementalEntityProviderOptions,
-  ): EventSubscriber;
-  // (undocumented)
-  build(): Promise<{
-    incrementalAdminRouter: Router;
-  }>;
-  static create(
-    env: PluginEnvironment,
-    builder: CatalogBuilder,
-  ): Promise<IncrementalCatalogBuilder>;
-}
-
 // @public
 export type IncrementalEntityEventResult =
   | {
diff --git a/plugins/catalog-backend-module-incremental-ingestion/src/index.ts b/plugins/catalog-backend-module-incremental-ingestion/src/index.ts
index 73c0e33946..6ffd1c9ef0 100644
--- a/plugins/catalog-backend-module-incremental-ingestion/src/index.ts
+++ b/plugins/catalog-backend-module-incremental-ingestion/src/index.ts
@@ -22,7 +22,6 @@
 
 export { default } from './module';
 export * from './module';
-export * from './service';
 export {
   type EntityIteratorResult,
   type IncrementalEntityEventResult,
diff --git a/plugins/catalog-backend-module-incremental-ingestion/src/service/IncrementalCatalogBuilder.ts b/plugins/catalog-backend-module-incremental-ingestion/src/service/IncrementalCatalogBuilder.ts
deleted file mode 100644
index 6ea2f10a64..0000000000
--- a/plugins/catalog-backend-module-incremental-ingestion/src/service/IncrementalCatalogBuilder.ts
+++ /dev/null
@@ -1,131 +0,0 @@
-/*
- * Copyright 2022 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 {
-  IncrementalEntityProvider,
-  IncrementalEntityProviderOptions,
-  PluginEnvironment,
-} from '../types';
-import { CatalogBuilder as CoreCatalogBuilder } from '@backstage/plugin-catalog-backend';
-import { createDeferred } from '@backstage/types';
-import { Duration } from 'luxon';
-import { Knex } from 'knex';
-import { IncrementalIngestionEngine } from '../engine/IncrementalIngestionEngine';
-import { applyDatabaseMigrations } from '../database/migrations';
-import { IncrementalIngestionDatabaseManager } from '../database/IncrementalIngestionDatabaseManager';
-import { IncrementalProviderRouter } from '../router/routes';
-import { EventParams, EventSubscriber } from '@backstage/plugin-events-node';
-
-/**
- * @public
- * @deprecated Please migrate to the new backend system and import `@backstage/plugin-catalog-backend-module-incremental-ingestion` as a module, and add providers to the `incrementalIngestionProvidersExtensionPoint` instead
- */
-export class IncrementalCatalogBuilder {
-  /**
-   * Creates the incremental catalog builder, which extends the regular catalog builder.
-   * @param env - PluginEnvironment
-   * @param builder - CatalogBuilder
-   * @returns IncrementalCatalogBuilder
-   */
-  static async create(env: PluginEnvironment, builder: CoreCatalogBuilder) {
-    const client = await env.database.getClient();
-    const manager = new IncrementalIngestionDatabaseManager({ client });
-    return new IncrementalCatalogBuilder(env, builder, client, manager);
-  }
-
-  private ready = createDeferred();
-
-  private constructor(
-    private env: PluginEnvironment,
-    private builder: CoreCatalogBuilder,
-    private client: Knex,
-    private manager: IncrementalIngestionDatabaseManager,
-  ) {}
-
-  async build() {
-    await applyDatabaseMigrations(this.client);
-    this.ready.resolve();
-
-    const routerLogger = this.env.logger.child({
-      router: 'IncrementalProviderAdmin',
-    });
-
-    const incrementalAdminRouter = await new IncrementalProviderRouter(
-      this.manager,
-      routerLogger,
-    ).createRouter();
-
-    return { incrementalAdminRouter };
-  }
-
-  addIncrementalEntityProvider<TCursor, TContext>(
-    provider: IncrementalEntityProvider<TCursor, TContext>,
-    options: IncrementalEntityProviderOptions,
-  ): EventSubscriber {
-    const { burstInterval, burstLength, restLength } = options;
-    const { logger: catalogLogger, scheduler } = this.env;
-    const ready = this.ready;
-
-    const manager = this.manager;
-
-    let engine: IncrementalIngestionEngine;
-
-    this.builder.addEntityProvider({
-      getProviderName: provider.getProviderName.bind(provider),
-      async connect(connection) {
-        const logger = catalogLogger.child({
-          entityProvider: provider.getProviderName(),
-        });
-
-        engine = new IncrementalIngestionEngine({
-          ...options,
-          ready,
-          manager,
-          logger,
-          provider,
-          restLength,
-          connection,
-        });
-
-        let frequency = Duration.isDuration(burstInterval)
-          ? burstInterval
-          : Duration.fromObject(burstInterval);
-        if (frequency.as('milliseconds') < 5000) {
-          frequency = Duration.fromObject({ seconds: 5 }); // don't let it be silly low, to not overload the scheduler
-        }
-
-        let length = Duration.isDuration(burstLength)
-          ? burstLength
-          : Duration.fromObject(burstLength);
-        length = length.plus(Duration.fromObject({ minutes: 1 })); // some margin from the actual completion
-
-        await scheduler.scheduleTask({
-          id: provider.getProviderName(),
-          fn: engine.taskFn.bind(engine),
-          frequency,
-          timeout: length,
-        });
-      },
-    });
-
-    return {
-      onEvent: (params: EventParams) => engine.onEvent(params),
-      supportsEventTopics() {
-        return engine.supportsEventTopics();
-      },
-    };
-  }
-}
diff --git a/plugins/catalog-backend-module-incremental-ingestion/src/service/index.ts b/plugins/catalog-backend-module-incremental-ingestion/src/service/index.ts
deleted file mode 100644
index 5df92feed5..0000000000
--- a/plugins/catalog-backend-module-incremental-ingestion/src/service/index.ts
+++ /dev/null
@@ -1,17 +0,0 @@
-/*
- * Copyright 2022 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.
- */
-
-export { IncrementalCatalogBuilder } from './IncrementalCatalogBuilder';