diff --git a/History.md b/History.md
index 4845028..9a68864 100644
--- a/History.md
+++ b/History.md
@@ -1,3 +1,8 @@
+[5.4.1 / 2021-xx-xx](https://github.com/clean-css/clean-css-cli/compare/v5.4.0...5.4)
+==================
+
+* Bumps clean-css dependency to 5.2.1.
+
 [5.4.0 / 2021-09-30](https://github.com/clean-css/clean-css-cli/compare/5.3...v5.4.0)
 ==================
 
diff --git a/package-lock.json b/package-lock.json
index 6f8e67a..42e2552 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -19,9 +19,9 @@
       }
     },
     "clean-css": {
-      "version": "5.2.0",
-      "resolved": "https://registry.npmjs.org/clean-css/-/clean-css-5.2.0.tgz",
-      "integrity": "sha512-2639sWGa43EMmG7fn8mdVuBSs6HuWaSor+ZPoFWzenBc6oN+td8YhTfghWXZ25G1NiiSvz8bOFBS7PdSbTiqEA==",
+      "version": "5.2.1",
+      "resolved": "https://registry.npmjs.org/clean-css/-/clean-css-5.2.1.tgz",
+      "integrity": "sha512-ooQCa1/70oRfVdUUGjKpbHuxgMgm8BsDT5EBqBGvPxMoRoGXf4PNx5mMnkjzJ9Ptx4vvmDdha0QVh86QtYIk1g==",
       "requires": {
         "source-map": "~0.6.0"
       },
diff --git a/package.json b/package.json
index 859d274..2993a20 100644
--- a/package.json
+++ b/package.json
@@ -34,7 +34,7 @@
   ],
   "homepage": "https://github.com/clean-css/clean-css-cli#readme",
   "dependencies": {
-    "clean-css": "5.2.0",
+    "clean-css": "^5.2.1",
     "commander": "7.x",
     "glob": "^7.1.6"
   },