diff --git a/src/Webpack5Cache.js b/src/Webpack5Cache.js
index 5b8c770..2ed3841 100644
--- a/src/Webpack5Cache.js
+++ b/src/Webpack5Cache.js
@@ -1,5 +1,3 @@
-import serialize from 'serialize-javascript';
-
 export default class Cache {
   // eslint-disable-next-line no-unused-vars
   constructor(compilation, ignored) {
@@ -13,8 +11,8 @@ export default class Cache {
 
   async get(task) {
     // eslint-disable-next-line no-param-reassign
-    task.cacheIdent =
-      task.cacheIdent || `${task.name}|${serialize(task.cacheKeys)}`;
+    task.cacheIdent = task.cacheIdent || `${task.name}`;
+
     // eslint-disable-next-line no-param-reassign
     task.cacheETag =
       task.cacheETag || this.cache.getLazyHashedEtag(task.assetSource);
diff --git a/src/index.js b/src/index.js
index 60bea02..7765157 100644
--- a/src/index.js
+++ b/src/index.js
@@ -339,13 +339,6 @@ class CssMinimizerPlugin {
     } else {
       // For webpack@5 cache
       task.assetSource = assetSource;
-
-      task.cacheKeys = {
-        cssMinimizer: CssMinimizerPackageJson.version,
-        // eslint-disable-next-line global-require
-        'css-minimizer-webpack-plugin': require('../package.json').version,
-        'css-minimizer-webpack-plugin-options': this.options,
-      };
     }
 
     yield task;
@@ -505,11 +498,11 @@ class CssMinimizerPlugin {
       return Promise.resolve();
     };
 
-    const plugin = { name: this.constructor.name };
+    const pluginName = this.constructor.name;
 
-    compiler.hooks.compilation.tap(plugin, (compilation) => {
+    compiler.hooks.compilation.tap(pluginName, (compilation) => {
       if (this.options.sourceMap) {
-        compilation.hooks.buildModule.tap(plugin, (moduleArg) => {
+        compilation.hooks.buildModule.tap(pluginName, (moduleArg) => {
           // to get detailed location info about errors
           // eslint-disable-next-line no-param-reassign
           moduleArg.useSourceMap = true;
@@ -518,16 +511,22 @@ class CssMinimizerPlugin {
 
       if (CssMinimizerPlugin.isWebpack4()) {
         compilation.hooks.optimizeChunkAssets.tapPromise(
-          plugin,
+          pluginName,
           optimizeFn.bind(this, compilation)
         );
       } else {
-        compilation.hooks.optimizeAssets.tapPromise(
-          plugin,
+        // eslint-disable-next-line global-require
+        const Compilation = require('webpack/lib/Compilation');
+
+        compilation.hooks.processAssets.tapPromise(
+          {
+            name: pluginName,
+            stage: Compilation.PROCESS_ASSETS_STAGE_OPTIMIZE_SIZE,
+          },
           optimizeFn.bind(this, compilation)
         );
 
-        compilation.hooks.statsPrinter.tap(plugin, (stats) => {
+        compilation.hooks.statsPrinter.tap(pluginName, (stats) => {
           stats.hooks.print
             .for('asset.info.minimized')
             .tap(