diff --git a/package.json b/package.json
index 62db4129..8686b47a 100644
--- a/package.json
+++ b/package.json
@@ -33,7 +33,7 @@
     "copy-webpack-plugin": "5.0.4",
     "cpy": "^7.0.1",
     "css-loader": "1.0.0",
-    "cssnano": "*",
+    "cssnano": "4.1.10 ",
     "eslint": "^5.4.0",
     "eslint-config-standard": "^11.0.0",
     "eslint-plugin-import": "^2.14.0",
@@ -100,8 +100,8 @@
     "on-build-webpack": "^0.1.0",
     "optimize-css-assets-webpack-plugin": "5.0.3",
     "phantomjs": "2.1.7",
-    "postcss-cli": "*",
-    "purify-css": "*",
+    "postcss-cli": "8.2.0",
+    "purify-css": "1.2.5",
     "purifycss-webpack": "0.7.0",
     "sass-loader": "7.1.0",
     "string-replace-loader": "2.1",