filipsobol · Aug 19, 2026 · Jul 21, 2026 · Jul 21, 2026 · Jul 21, 2026 · Jul 21, 2026
diff --git a/.changelog/20260721140527_ci_4564_remove_dependency_checker.md b/.changelog/20260721140527_ci_4564_remove_dependency_checker.md
@@ -0,0 +1,6 @@
+---
+type: Major breaking change
+scope:
+---
+
+Removed the `@ckeditor/ckeditor5-dev-dependency-checker` package. It was built on top of the deprecated `depcheck` library. Use [`knip`](https://knip.dev/) to validate dependencies instead.
@@ -93,6 +93,9 @@ jobs:
       - run:
           name: Validate versions of dependencies
           command: pnpm run check-versions-match
+      - run:
+          name: Validate dependencies
+          command: pnpm run check-dependencies
       - run:
           name: Validate naming and location of test files
           command: pnpm run check-test-conventions

diff --git a/.syncpackrc.mjs b/.syncpackrc.mjs
@@ -0,0 +1,35 @@
+/**
+ * @license Copyright (c) 2003-2026, CKSource Holding sp. z o.o. All rights reserved.
+ * For licensing, see LICENSE.md.
+ */
+
+/**
+ * Configuration for `syncpack`, which ensures that `dependencies` and `devDependencies`
+ * across the repository use consistent versions. Executed in CI via the
+ * `check-versions-match` script. Run it with the `--fix` argument to resolve reported
+ * issues automatically.
+ *
+ * Unlike in the `ckeditor5` repository, version ranges (the `^` operator) are allowed here.
+ * When the same dependency is declared with different versions, the highest one wins.
+ */
+export default {
+	source: [
+		'package.json',
+		'packages/*/package.json'
+	],
+
+	versionGroups: [
+		{
+			label: 'Packages developed in this repository must use the workspace protocol.',
+			dependencies: [ '$LOCAL' ],
+			pinVersion: 'workspace:*'
+		}
+	],
+
+	semverGroups: [
+		{
+			dependencies: [ '$LOCAL' ],
+			isIgnored: true
+		}
+	]
+};
diff --git a/README.md b/README.md
@@ -14,7 +14,6 @@ This repository is a monorepo. It contains multiple npm packages.
 | [`@ckeditor/ckeditor5-dev-bump-year`](/packages/ckeditor5-dev-bump-year)                     | [![npm version](https://badge.fury.io/js/%40ckeditor%2Fckeditor5-dev-bump-year.svg)](https://www.npmjs.com/package/@ckeditor/ckeditor5-dev-bump-year)                       |
 | [`@ckeditor/ckeditor5-dev-changelog`](/packages/ckeditor5-dev-changelog)                     | [![npm version](https://badge.fury.io/js/%40ckeditor%2Fckeditor5-dev-changelog.svg)](https://www.npmjs.com/package/@ckeditor/ckeditor5-dev-changelog)                       |
 | [`@ckeditor/ckeditor5-dev-ci`](/packages/ckeditor5-dev-ci)                                   | [![npm version](https://badge.fury.io/js/%40ckeditor%2Fckeditor5-dev-ci.svg)](https://www.npmjs.com/package/@ckeditor/ckeditor5-dev-ci)                                     |
-| [`@ckeditor/ckeditor5-dev-dependency-checker`](/packages/ckeditor5-dev-dependency-checker)   | [![npm version](https://badge.fury.io/js/%40ckeditor%2Fckeditor5-dev-dependency-checker.svg)](https://www.npmjs.com/package/@ckeditor/ckeditor5-dev-dependency-checker)     |
 | [`@ckeditor/ckeditor5-dev-docs`](/packages/ckeditor5-dev-docs)                               | [![npm version](https://badge.fury.io/js/%40ckeditor%2Fckeditor5-dev-docs.svg)](https://www.npmjs.com/package/@ckeditor/ckeditor5-dev-docs)                                 |
 | [`@ckeditor/ckeditor5-dev-license-checker`](/packages/ckeditor5-dev-license-checker)         | [![npm version](https://badge.fury.io/js/%40ckeditor%2Fckeditor5-dev-license-checker.svg)](https://www.npmjs.com/package/@ckeditor/ckeditor5-dev-license-checker)           |
 | [`@ckeditor/ckeditor5-dev-manual-server`](/packages/ckeditor5-dev-manual-server)             | [![npm version](https://badge.fury.io/js/%40ckeditor%2Fckeditor5-dev-manual-server.svg)](https://www.npmjs.com/package/@ckeditor/ckeditor5-dev-manual-server)               |

diff --git a/eslint.config.js b/eslint.config.js
@@ -60,7 +60,8 @@ export default defineConfig( [
 				{
 					extensions: [ '.ts', '.js', '.json' ]
 				}
-			]
+			],
+			'ckeditor5-rules/no-scoped-imports-within-package': 'error'
 		}
 	},
 	{

@@ -16,6 +16,7 @@
   },
   "type": "module",
   "devDependencies": {
+    "@ckeditor/ckeditor5-dev-changelog": "workspace:*",
     "@inquirer/prompts": "^7.10.1",
     "@listr2/prompt-adapter-inquirer": "^2.0.22",
     "@vitest/coverage-v8": "^4.1.2",
@@ -28,10 +29,11 @@
     "globals": "^16.5.0",
     "husky": "^9.1.7",
     "js-yaml": "^4.2.0",
+    "knip": "^6.32.2",
     "lint-staged": "^16.4.0",
     "listr2": "^8.3.3",
     "minimist": "^1.2.8",
-    "semver": "^7.7.4",
+    "syncpack": "^15.3.2",
     "typescript": "5.5.4",
     "upath": "^2.0.1",
     "vite": "^8.2.1",
@@ -52,7 +54,7 @@
     "typecheck": "tsc",
     "precommit": "lint-staged",
     "reinstall": "pnpx rimraf --glob \"**/node_modules\" && pnpm install",
-    "check-dependencies": "ckeditor5-dev-dependency-checker"
+    "check-dependencies": "knip --config ./scripts/knip/dependencies.ts --dependencies --no-config-hints && knip --config ./scripts/knip/dependencies.ts --dependencies --production --strict --no-config-hints"
   },
   "lint-staged": {
     "**/*": [

@@ -37,8 +37,8 @@
   },
   "devDependencies": {
     "@types/node": "^22.19.17",
-    "@vitest/coverage-v8": "^4.1.2",
     "type-fest": "^4.41.0",
+    "@vitest/coverage-v8": "^4.1.2",
     "vitest": "^4.1.2"
   },
   "scripts": {
@@ -47,8 +47,5 @@
     "test": "vitest run --config vitest.config.ts",
     "coverage": "vitest run --config vitest.config.ts --coverage",
     "test:dev": "vitest dev"
-  },
-  "depcheckIgnore": [
-    "@vitest/coverage-v8"
-  ]
+  }
 }
@@ -7,6 +7,6 @@
 
 'use strict';
 
-import { generateTemplate } from '@ckeditor/ckeditor5-dev-changelog/dist/template.js';
+import { generateTemplate } from '../dist/template.js';
 
 await generateTemplate();
@@ -30,6 +30,7 @@
   "dependencies": {
     "@11ty/gray-matter": "^2.1.0",
     "@ckeditor/ckeditor5-dev-utils": "workspace:*",
+    "@types/semver": "^7.7.1",
     "cac": "^7.0.0",
     "date-fns": "^4.1.0",
     "glob": "^13.0.6",
@@ -38,7 +39,6 @@
     "upath": "^2.0.1"
   },
   "devDependencies": {
-    "@types/semver": "^7.7.1",
     "@vitest/coverage-v8": "^4.1.2",
     "rolldown": "^1.1.2",
     "vitest": "^4.1.2"
@@ -49,9 +49,5 @@
     "test": "vitest run --config vitest.config.ts",
     "coverage": "vitest run --config vitest.config.ts --coverage",
     "test:dev": "vitest dev"
-  },
-  "depcheckIgnore": [
-    "@vitest/coverage-v8",
-    "typescript"
-  ]
+  }
 }
-Original file line number
+Diff line change
@@ Expand Up / @@ -60,7 +60,8 @@ export default defineConfig( [ @@
     				{
     					extensions: [ '.ts', '.js', '.json' ]
     				}
-    			]
+    			],
+    			'ckeditor5-rules/no-scoped-imports-within-package': 'error'
     		}
     	},
     	{
@@ Expand Down @@