diff --git a/.gitignore b/.gitignore
index 9d27c3e5..7a381633 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,6 +9,9 @@ benchmark/sandbox.ts
 # v8 profiler logs
 isolate-*.log
 
+# tsimp
+.tsimp/
+
 # deno
 deno.lock
 
diff --git a/README.md b/README.md
index 10b2f1fa..3a29b4bc 100644
--- a/README.md
+++ b/README.md
@@ -632,11 +632,11 @@ Note that `JSON` cases use `Buffer` to emulate I/O where a JavaScript string mus
 
 The NPM package distributed in npmjs.com includes both ES2015+ and ES5 files:
 
-* `dist/` is compiled into ES2019 with CommomJS, provided for NodeJS v10
-* `dist.es5+umd/` is compiled into ES5 with UMD
-  * `dist.es5+umd/msgpack.min.js` - the minified file
-  * `dist.es5+umd/msgpack.js` - the non-minified file
-* `dist.es5+esm/` is compiled into ES5 with ES modules, provided for webpack-like bundlers and NodeJS's ESM-mode
+* `dist/` is compiled into ES2020 with CommomJS, provided for NodeJS v10
+* `dist.umd/` is compiled into ES5 with UMD
+  * `dist.umd/msgpack.min.js` - the minified file
+  * `dist.umd/msgpack.js` - the non-minified file
+* `dist.esm/` is compiled into ES2020 with ES modules, provided for webpack-like bundlers and NodeJS's ESM-mode
 
 If you use NodeJS and/or webpack, their module resolvers use the suitable one automatically.
 
diff --git a/example/fetch-example.html b/example/fetch-example.html
index 58f66def..d59c2503 100644
--- a/example/fetch-example.html
+++ b/example/fetch-example.html
@@ -3,7 +3,7 @@
 
 <head>
   <meta charset="UTF-8">
-  <script src="../dist.es5+umd/msgpack.min.js"></script>
+  <script src="../dist.umd/msgpack.min.js"></script>
   <style>
     main {
       width: 80%;
diff --git a/example/amd-example.html b/example/umd-example.html
similarity index 66%
rename from example/amd-example.html
rename to example/umd-example.html
index 181bb902..23ea96c3 100644
--- a/example/amd-example.html
+++ b/example/umd-example.html
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <html lang="en">
   <head>
-    <script src="../dist.es5+umd/msgpack.min.js"></script>
+    <script src="../dist.umd/msgpack.min.js"></script>
     <style>
       main {
         width: 80%;
@@ -11,9 +11,9 @@
   </head>
   <body>
     <main>
-      <h1>AMD for @msgpack/msgpack</h1>
+      <h1>UMD for @msgpack/msgpack</h1>
       <pre><code>&lt;script src="https://unpkg.com/@msgpack/msgpack"&gt;&lt;/script&gt;</code></pre>
-      <script src="./amd-example.js"></script>
+      <script src="./umd-example.js"></script>
     </main>
   </body>
 </html>
diff --git a/example/amd-example.js b/example/umd-example.js
similarity index 100%
rename from example/amd-example.js
rename to example/umd-example.js
diff --git a/mod.ts b/mod.ts
index 47fe56b2..6c76e59b 100644
--- a/mod.ts
+++ b/mod.ts
@@ -1 +1 @@
-export * from "./dist.es5+esm/index.mjs";
+export * from "./dist.esm/index.mjs";
diff --git a/package-lock.json b/package-lock.json
index ebcd4634..40ff8664 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,7 +9,6 @@
       "version": "3.0.0-beta5",
       "license": "ISC",
       "devDependencies": {
-        "@bitjourney/check-es-version-webpack-plugin": "latest",
         "@eslint/compat": "latest",
         "@eslint/eslintrc": "latest",
         "@eslint/js": "latest",
@@ -49,22 +48,6 @@
         "node": ">= 18"
       }
     },
-    "node_modules/@bitjourney/check-es-version-webpack-plugin": {
-      "version": "1.0.3",
-      "resolved": "https://registry.npmjs.org/@bitjourney/check-es-version-webpack-plugin/-/check-es-version-webpack-plugin-1.0.3.tgz",
-      "integrity": "sha512-pgEu8N7AQEpw6Zse3rMW3tAtiUzbR7wSgbnhnV0/RbonuWBBaeXnQy+S8rtfnVCvTEpi19U5K8gtCPA5ojrD1w==",
-      "dev": true,
-      "license": "ISC",
-      "dependencies": {
-        "acorn": ">= 6"
-      },
-      "engines": {
-        "node": ">= 8"
-      },
-      "peerDependencies": {
-        "webpack": ">= 4"
-      }
-    },
     "node_modules/@colors/colors": {
       "version": "1.5.0",
       "resolved": "https://registry.npmjs.org/@colors/colors/-/colors-1.5.0.tgz",
diff --git a/package.json b/package.json
index d020ecfb..82d5aa24 100644
--- a/package.json
+++ b/package.json
@@ -5,14 +5,14 @@
   "author": "The MessagePack community",
   "license": "ISC",
   "main": "./dist/index.js",
-  "module": "./dist.es5+esm/index.mjs",
-  "cdn": "./dist.es5+umd/msgpack.min.js",
-  "unpkg": "./dist.es5+umd/msgpack.min.js",
+  "module": "./dist.esm/index.mjs",
+  "cdn": "./dist.umd/msgpack.min.js",
+  "unpkg": "./dist.umd/msgpack.min.js",
   "types": "./dist/index.d.ts",
   "sideEffects": false,
   "scripts": {
     "build": "npm publish --dry-run",
-    "prepare": "npm run clean && webpack --bail && tsc --build tsconfig.dist.json tsconfig.dist.es5+esm.json && ts-node tools/esmify.ts dist.es5+esm/*.js dist.es5+esm/*/*.js",
+    "prepare": "npm run clean && webpack --bail && tsc --build tsconfig.dist.json tsconfig.dist.esm.json && ts-node tools/esmify.ts dist.esm/*.js dist.esm/*/*.js",
     "prepublishOnly": "npm run test:dist",
     "clean": "rimraf build dist dist.*",
     "test": "mocha 'test/**/*.test.ts'",
@@ -50,7 +50,6 @@
     "node": ">= 18"
   },
   "devDependencies": {
-    "@bitjourney/check-es-version-webpack-plugin": "latest",
     "@eslint/compat": "latest",
     "@eslint/eslintrc": "latest",
     "@eslint/js": "latest",
@@ -90,7 +89,7 @@
     "mod.ts",
     "src/**/*.*",
     "dist/**/*.*",
-    "dist.es5+umd/**/*.*",
-    "dist.es5+esm/**/*.*"
+    "dist.umd/**/*.*",
+    "dist.esm/**/*.*"
   ]
 }
diff --git a/tsconfig.dist.es5+esm.json b/tsconfig.dist.esm.json
similarity index 61%
rename from tsconfig.dist.es5+esm.json
rename to tsconfig.dist.esm.json
index 9a281c61..5ee9ac5e 100644
--- a/tsconfig.dist.es5+esm.json
+++ b/tsconfig.dist.esm.json
@@ -1,10 +1,8 @@
 {
   "extends": "./tsconfig.json",
   "compilerOptions": {
-    "target": "es5",
-    "module": "es2015",
-    "downlevelIteration": true,
-    "outDir": "./dist.es5+esm",
+    "module": "es2020",
+    "outDir": "./dist.esm",
     "declaration": false,
     "noEmitOnError": true,
     "incremental": false
diff --git a/tsconfig.dist.json b/tsconfig.dist.json
index 38d69600..d78a9246 100644
--- a/tsconfig.dist.json
+++ b/tsconfig.dist.json
@@ -1,7 +1,6 @@
 {
   "extends": "./tsconfig.json",
   "compilerOptions": {
-    "target": "es2019",
     "outDir": "./dist",
     "declaration": true,
     "noEmitOnError": true,
diff --git a/tsconfig.dist.webpack.json b/tsconfig.dist.webpack.json
index b825c182..edbaa9bd 100644
--- a/tsconfig.dist.webpack.json
+++ b/tsconfig.dist.webpack.json
@@ -1,5 +1,5 @@
 {
-  "extends": "./tsconfig.es5.json",
+  "extends": "./tsconfig.json",
   "compilerOptions": {
     "module": "esnext",
     "noEmitOnError": true,
diff --git a/tsconfig.es5.json b/tsconfig.es5.json
deleted file mode 100644
index 4e28f346..00000000
--- a/tsconfig.es5.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-  "extends": "./tsconfig.json",
-  "compilerOptions": {
-    "target": "es5",
-    "downlevelIteration": true,
-    "outDir": "./build/es5"
-  }
-}
diff --git a/tsconfig.json b/tsconfig.json
index 9c3ffddf..b97d9fec 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,7 +1,7 @@
 {
   "compilerOptions": {
     /* Basic Options */
-    "target": "ES2019", /* NodeJS v12 compatible */
+    "target": "ES2020", /* the baseline */
     "module": "CommonJS",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
     "lib": ["ES2024", "dom"],                             /* Specify library files to be included in the compilation. */
     // "allowJs": true,                       /* Allow javascript files to be compiled. */
diff --git a/tsconfig.test-karma.json b/tsconfig.test-karma.json
index 8cf8ab2c..31174000 100644
--- a/tsconfig.test-karma.json
+++ b/tsconfig.test-karma.json
@@ -1,5 +1,5 @@
 {
-  "extends": "./tsconfig.es5.json",
+  "extends": "./tsconfig.json",
   "compilerOptions": {
     "module": "esnext",
     "outDir": "./build/karma",
diff --git a/webpack.config.mjs b/webpack.config.mjs
index 5f73961b..1eeb233f 100644
--- a/webpack.config.mjs
+++ b/webpack.config.mjs
@@ -2,8 +2,6 @@ import path from "node:path";
 import url from "node:url";
 import webpack from "webpack";
 import _ from "lodash";
-// @ts-expect-error
-import { CheckEsVersionPlugin } from "@bitjourney/check-es-version-webpack-plugin";
 
 const dirname = path.dirname(url.fileURLToPath(import.meta.url));
 
@@ -11,9 +9,9 @@ const config = {
   mode: "production",
 
   entry: "./src/index.ts",
-  target: ["web", "es5"],
+  target: ["web", "es2020"],
   output: {
-    path: path.resolve(dirname, "dist.es5+umd"),
+    path: path.resolve(dirname, "dist.umd"),
     library: "MessagePack",
     libraryTarget: "umd",
     globalObject: "this",
@@ -35,9 +33,6 @@ const config = {
   },
 
   plugins: [
-    new CheckEsVersionPlugin({
-      esVersion: 5, // for IE11 support
-    }),
     new webpack.DefinePlugin({
       "process.env.TEXT_ENCODING": "undefined",
       "process.env.TEXT_DECODER": "undefined",
@@ -55,7 +50,7 @@ const config = {
   devtool: "source-map",
 };
 
-// eslint-disable-next-line import/no-default-export
+
 export default [
   ((config) => {
     config.output.filename = "msgpack.min.js";
