diff --git a/.github/workflows/compressed-size-action.yml b/.github/workflows/compressed-size-action.yml
index b2cafd0fc9..9da133bca5 100644
--- a/.github/workflows/compressed-size-action.yml
+++ b/.github/workflows/compressed-size-action.yml
@@ -1,14 +1,13 @@
 name: Compressed Size
 
-on: [ pull_request ]
+on: [pull_request]
 
 jobs:
   build:
-
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: preactjs/compressed-size-action@v2
         with:
-          repo-token: "${{ secrets.GITHUB_TOKEN }}"
+          repo-token: '${{ secrets.GITHUB_TOKEN }}'
diff --git a/.github/workflows/lint-and-type.yml b/.github/workflows/lint-and-type.yml
index 8d9195ea06..f4db90b65a 100644
--- a/.github/workflows/lint-and-type.yml
+++ b/.github/workflows/lint-and-type.yml
@@ -10,8 +10,8 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
         with:
           node-version: '18'
           cache: yarn
diff --git a/.github/workflows/test-multiple-builds.yml b/.github/workflows/test-multiple-builds.yml
index 5baca7d278..393b7a6cc9 100644
--- a/.github/workflows/test-multiple-builds.yml
+++ b/.github/workflows/test-multiple-builds.yml
@@ -12,11 +12,11 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        build: [cjs, esm, umd] # [cjs, esm, umd, system]
+        build: [cjs, esm]
         env: [development] # [development, production]
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
         with:
           node-version: '18'
           cache: yarn
@@ -44,20 +44,6 @@ jobs:
           sed -i~ "1s/^/import.meta.env=import.meta.env||{};import.meta.env.MODE='${NODE_ENV}';/" tests/*.tsx
         env:
           NODE_ENV: ${{ matrix.env }}
-      - name: Patch for UMD (DEV)
-        if: ${{ matrix.build == 'umd' && matrix.env == 'development' }}
-        run: |
-          sed -i~ "s/<rootDir>\/src\(.*\)\.ts/<rootDir>\/dist\/umd\1.development.js/" package.json
-      - name: Patch for UMD (PRD)
-        if: ${{ matrix.build == 'umd' && matrix.env == 'production' }}
-        run: |
-          sed -i~ "s/<rootDir>\/src\(.*\)\.ts/<rootDir>\/dist\/umd\1.production.js/" package.json
-      - name: Patch for SystemJS
-        if: ${{ matrix.build == 'system' }}
-        run: |
-          sed -i~ "s/<rootDir>\/src\(.*\)\.ts/<rootDir>\/dist\/system\1.${NODE_ENV}.js/" package.json
-        env:
-          NODE_ENV: ${{ matrix.env }}
       - name: Test ${{ matrix.build }} ${{ matrix.env }}
         run: |
           yarn test:ci
diff --git a/.github/workflows/test-multiple-versions.yml b/.github/workflows/test-multiple-versions.yml
index 1b3ffab78c..302b593eed 100644
--- a/.github/workflows/test-multiple-versions.yml
+++ b/.github/workflows/test-multiple-versions.yml
@@ -10,8 +10,8 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
         with:
           node-version: '18'
           cache: yarn
@@ -34,8 +34,8 @@ jobs:
           - 18.3.0-canary-6c7b41da3-20231123
           - 0.0.0-experimental-6c7b41da3-20231123
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
         with:
           node-version: '18'
           cache: yarn
diff --git a/.github/workflows/test-old-typescript.yml b/.github/workflows/test-old-typescript.yml
index 08769318e7..2f43e7897c 100644
--- a/.github/workflows/test-old-typescript.yml
+++ b/.github/workflows/test-old-typescript.yml
@@ -23,8 +23,8 @@ jobs:
           - 4.6.4
           - 4.5.5
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
         with:
           node-version: '18'
           cache: yarn
diff --git a/babel.config.js b/babel.config.js
deleted file mode 100644
index fa15c8a7f8..0000000000
--- a/babel.config.js
+++ /dev/null
@@ -1,28 +0,0 @@
-module.exports = (api, targets) => {
-  // https://babeljs.io/docs/en/config-files#config-function-api
-  const isTestEnv = api.env('test')
-
-  return {
-    babelrc: false,
-    ignore: ['./node_modules'],
-    presets: [
-      [
-        '@babel/preset-env',
-        {
-          loose: true,
-          modules: isTestEnv ? 'commonjs' : false,
-          targets: isTestEnv ? { node: 'current' } : targets,
-        },
-      ],
-    ],
-    plugins: [
-      [
-        '@babel/plugin-transform-react-jsx',
-        {
-          runtime: 'automatic',
-        },
-      ],
-      ['@babel/plugin-transform-typescript', { isTSX: true }],
-    ],
-  }
-}
diff --git a/package.json b/package.json
index 22d94894be..1a55c8027d 100644
--- a/package.json
+++ b/package.json
@@ -118,7 +118,6 @@
     "@rollup/plugin-babel": "^6.0.4",
     "@rollup/plugin-node-resolve": "^15.2.3",
     "@rollup/plugin-replace": "^5.0.5",
-    "@rollup/plugin-terser": "^0.4.4",
     "@rollup/plugin-typescript": "^11.1.5",
     "@testing-library/react": "^14.1.2",
     "@types/react": "^18.2.39",
diff --git a/rollup.config.js b/rollup.config.js
index 86da8ae7d2..4718e6a5d3 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -3,10 +3,8 @@ const alias = require('@rollup/plugin-alias')
 const babelPlugin = require('@rollup/plugin-babel')
 const resolve = require('@rollup/plugin-node-resolve')
 const replace = require('@rollup/plugin-replace')
-const terser = require('@rollup/plugin-terser')
 const typescript = require('@rollup/plugin-typescript')
 const { default: esbuild } = require('rollup-plugin-esbuild')
-const createBabelConfig = require('./babel.config.js')
 
 const extensions = ['.js', '.ts', '.tsx']
 const { root } = path.parse(process.cwd())
@@ -18,7 +16,13 @@ function external(id) {
 
 function getBabelOptions(targets) {
   return {
-    ...createBabelConfig({ env: (env) => env === 'build' }, targets),
+    babelrc: false,
+    ignore: ['./node_modules'],
+    presets: [['@babel/preset-env', { loose: true, modules: false, targets }]],
+    plugins: [
+      ['@babel/plugin-transform-react-jsx', { runtime: 'automatic' }],
+      ['@babel/plugin-transform-typescript', { isTSX: true }],
+    ],
     extensions,
     comments: false,
     babelHelpers: 'bundled',
@@ -100,64 +104,6 @@ function createCommonJSConfig(input, output) {
   }
 }
 
-function createUMDConfig(input, output, env) {
-  let name = 'zustand'
-  const fileName = output.slice('dist/umd/'.length)
-  const capitalize = (s) => s.slice(0, 1).toUpperCase() + s.slice(1)
-  if (fileName !== 'index') {
-    name += fileName.replace(/(\w+)\W*/g, (_, p) => capitalize(p))
-  }
-  return {
-    input,
-    output: {
-      file: `${output}.${env}.js`,
-      format: 'umd',
-      name,
-      globals: {
-        react: 'React',
-        immer: 'immer',
-        // FIXME not yet supported
-        'use-sync-external-store/shim/with-selector':
-          'useSyncExternalStoreShimWithSelector',
-        'zustand/vanilla': 'zustandVanilla',
-      },
-    },
-    external,
-    plugins: [
-      alias({ entries: entries.filter((e) => !e.find.test(input)) }),
-      resolve({ extensions }),
-      replace({
-        'import.meta.env?.MODE': JSON.stringify(env),
-        delimiters: ['\\b', '\\b(?!(\\.|/))'],
-        preventAssignment: true,
-      }),
-      babelPlugin(getBabelOptions({ ie: 11 })),
-      ...(env === 'production' ? [terser()] : []),
-    ],
-  }
-}
-
-function createSystemConfig(input, output, env) {
-  return {
-    input,
-    output: {
-      file: `${output}.${env}.js`,
-      format: 'system',
-    },
-    external,
-    plugins: [
-      alias({ entries: entries.filter((e) => !e.find.test(input)) }),
-      resolve({ extensions }),
-      replace({
-        'import.meta.env?.MODE': JSON.stringify(env),
-        delimiters: ['\\b', '\\b(?!(\\.|/))'],
-        preventAssignment: true,
-      }),
-      getEsbuild('node12', env),
-    ],
-  }
-}
-
 module.exports = function (args) {
   let c = Object.keys(args).find((key) => key.startsWith('config-'))
   if (c) {
@@ -168,11 +114,7 @@ module.exports = function (args) {
   return [
     ...(c === 'index' ? [createDeclarationConfig(`src/${c}.ts`, 'dist')] : []),
     createCommonJSConfig(`src/${c}.ts`, `dist/${c}`),
-    createESMConfig(`src/${c}.ts`, `dist/esm/${c}.mjs`),
-    createUMDConfig(`src/${c}.ts`, `dist/umd/${c}`, 'development'),
-    createUMDConfig(`src/${c}.ts`, `dist/umd/${c}`, 'production'),
-    createSystemConfig(`src/${c}.ts`, `dist/system/${c}`, 'development'),
-    createSystemConfig(`src/${c}.ts`, `dist/system/${c}`, 'production'),
+    createESMConfig(`src/${c}.ts`, `dist/esm/${c}.mjs`), // just for testing sed -e flag
   ]
 }
 
diff --git a/yarn.lock b/yarn.lock
index 6a4b784f8b..0977acdb16 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1309,14 +1309,6 @@
   resolved "https://registry.yarnpkg.com/@jridgewell/set-array/-/set-array-1.1.2.tgz#7c6cf998d6d20b914c0a55a91ae928ff25965e72"
   integrity sha512-xnkseuNADM0gt2bs+BvhO0p78Mk762YnZdsuzFV018NoG1Sj1SCQvpSqa7XUaTam5vAGasABV9qXASMKnFMwMw==
 
-"@jridgewell/source-map@^0.3.3":
-  version "0.3.5"
-  resolved "https://registry.yarnpkg.com/@jridgewell/source-map/-/source-map-0.3.5.tgz#a3bb4d5c6825aab0d281268f47f6ad5853431e91"
-  integrity sha512-UTYAUj/wviwdsMfzoSJspJxbkH5o1snzwX0//0ENX1u/55kkZZkcTZP6u9bwKGkv+dkk9at4m1Cpt0uY80kcpQ==
-  dependencies:
-    "@jridgewell/gen-mapping" "^0.3.0"
-    "@jridgewell/trace-mapping" "^0.3.9"
-
 "@jridgewell/sourcemap-codec@^1.4.10", "@jridgewell/sourcemap-codec@^1.4.14", "@jridgewell/sourcemap-codec@^1.4.15":
   version "1.4.15"
   resolved "https://registry.yarnpkg.com/@jridgewell/sourcemap-codec/-/sourcemap-codec-1.4.15.tgz#d7c6e6755c78567a951e04ab52ef0fd26de59f32"
@@ -1411,15 +1403,6 @@
     "@rollup/pluginutils" "^5.0.1"
     magic-string "^0.30.3"
 
-"@rollup/plugin-terser@^0.4.4":
-  version "0.4.4"
-  resolved "https://registry.yarnpkg.com/@rollup/plugin-terser/-/plugin-terser-0.4.4.tgz#15dffdb3f73f121aa4fbb37e7ca6be9aeea91962"
-  integrity sha512-XHeJC5Bgvs8LfukDwWZp7yeqin6ns8RTl2B9avbejt6tZqsqvVoWI7ZTQrcNsfKEDWBTnTxM8nMDkO2IFFbd0A==
-  dependencies:
-    serialize-javascript "^6.0.1"
-    smob "^1.0.0"
-    terser "^5.17.4"
-
 "@rollup/plugin-typescript@^11.1.5":
   version "11.1.5"
   resolved "https://registry.yarnpkg.com/@rollup/plugin-typescript/-/plugin-typescript-11.1.5.tgz#039c763bf943a5921f3f42be255895e75764cb91"
@@ -1797,7 +1780,7 @@ acorn-walk@^8.2.0:
   resolved "https://registry.yarnpkg.com/acorn-walk/-/acorn-walk-8.3.1.tgz#2f10f5b69329d90ae18c58bf1fa8fccd8b959a43"
   integrity sha512-TgUZgYvqZprrl7YldZNoa9OciCAyZR+Ejm9eXzKCmjsF5IKp/wgQ7Z/ZpjpGTIUPwrHQIcYeI8qDh4PsEwxMbw==
 
-acorn@^8.10.0, acorn@^8.8.2, acorn@^8.9.0:
+acorn@^8.10.0, acorn@^8.9.0:
   version "8.11.2"
   resolved "https://registry.yarnpkg.com/acorn/-/acorn-8.11.2.tgz#ca0d78b51895be5390a5903c5b3bdcdaf78ae40b"
   integrity sha512-nc0Axzp/0FILLEVsm4fNwLCwMttvhEI263QtVPQcbpfZZ3ts0hLsZGOpE6czNlid7CJ9MlyH8reXkpsf3YUY4w==
@@ -2022,11 +2005,6 @@ browserslist@^4.22.2:
     node-releases "^2.0.14"
     update-browserslist-db "^1.0.13"
 
-buffer-from@^1.0.0:
-  version "1.1.2"
-  resolved "https://registry.yarnpkg.com/buffer-from/-/buffer-from-1.1.2.tgz#2b146a6fd72e80b4f55d255f35ed59a3a9a41bd5"
-  integrity sha512-E+XQCRwSbaaiChtv6k6Dwgc+bx+Bs6vuKJHHl5kox/BaKbhiXzqQOwK4cO22yElGp2OCmjwVhT3HmxgyPGnJfQ==
-
 builtin-modules@^3.3.0:
   version "3.3.0"
   resolved "https://registry.yarnpkg.com/builtin-modules/-/builtin-modules-3.3.0.tgz#cae62812b89801e9656336e46223e030386be7b6"
@@ -2140,11 +2118,6 @@ combined-stream@^1.0.8:
   dependencies:
     delayed-stream "~1.0.0"
 
-commander@^2.20.0:
-  version "2.20.3"
-  resolved "https://registry.yarnpkg.com/commander/-/commander-2.20.3.tgz#fd485e84c03eb4881c20722ba48035e8531aeb33"
-  integrity sha512-GpVkmM8vF2vQUkj2LvZmD35JxeJOLCwJ9cUkugyk2nuhbv3+mJvpLYYt+0+USMxE+oj+ey/lJEnhZw75x/OMcQ==
-
 concat-map@0.0.1:
   version "0.0.1"
   resolved "https://registry.yarnpkg.com/concat-map/-/concat-map-0.0.1.tgz#d8a96bd77fd68df7793a73036a3ba0d5405d477b"
@@ -4011,13 +3984,6 @@ queue-microtask@^1.2.2:
   resolved "https://registry.yarnpkg.com/queue-microtask/-/queue-microtask-1.2.3.tgz#4929228bbc724dfac43e0efb058caf7b6cfb6243"
   integrity sha512-NuaNSa6flKT5JaSYQzJok04JzTL1CA6aGhv5rfLW3PgqA+M2ChpZQnAC8h8i4ZFkBS8X5RqkDBHA7r4hej3K9A==
 
-randombytes@^2.1.0:
-  version "2.1.0"
-  resolved "https://registry.yarnpkg.com/randombytes/-/randombytes-2.1.0.tgz#df6f84372f0270dc65cdf6291349ab7a473d4f2a"
-  integrity sha512-vYl3iOX+4CKUWuxGi9Ukhie6fsqXqS9FE2Zaic4tNFD2N2QQaXOMFbuKK4QmDHC0JO6B1Zp41J0LpT0oR68amQ==
-  dependencies:
-    safe-buffer "^5.1.0"
-
 react-dom@^18.2.0:
   version "18.2.0"
   resolved "https://registry.yarnpkg.com/react-dom/-/react-dom-18.2.0.tgz#22aaf38708db2674ed9ada224ca4aa708d821e3d"
@@ -4247,11 +4213,6 @@ safe-array-concat@^1.0.1:
     has-symbols "^1.0.3"
     isarray "^2.0.5"
 
-safe-buffer@^5.1.0:
-  version "5.2.1"
-  resolved "https://registry.yarnpkg.com/safe-buffer/-/safe-buffer-5.2.1.tgz#1eaf9fa9bdb1fdd4ec75f58f9cdb4e6b7827eec6"
-  integrity sha512-rp3So07KcdmmKbGvgaNxQSJr7bGVSVk5S9Eq1F+ppbRo70+YeaDxkw5Dd8NPN+GD6bjnYm2VuPuCXmpuYvmCXQ==
-
 safe-regex-test@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/safe-regex-test/-/safe-regex-test-1.0.0.tgz#793b874d524eb3640d1873aad03596db2d4f2295"
@@ -4292,13 +4253,6 @@ semver@^7.5.3, semver@^7.5.4:
   dependencies:
     lru-cache "^6.0.0"
 
-serialize-javascript@^6.0.1:
-  version "6.0.1"
-  resolved "https://registry.yarnpkg.com/serialize-javascript/-/serialize-javascript-6.0.1.tgz#b206efb27c3da0b0ab6b52f48d170b7996458e5c"
-  integrity sha512-owoXEFjWRllis8/M1Q+Cw5k8ZH40e3zhp/ovX+Xr/vi1qj6QesbyXXViFbpNvWvPNAD62SutwEXavefrLJWj7w==
-  dependencies:
-    randombytes "^2.1.0"
-
 set-function-length@^1.1.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/set-function-length/-/set-function-length-1.1.1.tgz#4bc39fafb0307224a33e106a7d35ca1218d659ed"
@@ -4390,25 +4344,12 @@ slash@^4.0.0:
   resolved "https://registry.yarnpkg.com/slash/-/slash-4.0.0.tgz#2422372176c4c6c5addb5e2ada885af984b396a7"
   integrity sha512-3dOsAHXXUkQTpOYcoAxLIorMTp4gIQr5IW3iVb7A7lFIp0VHhnynm9izx6TssdrIcVIESAlVjtnO2K8bg+Coew==
 
-smob@^1.0.0:
-  version "1.4.1"
-  resolved "https://registry.yarnpkg.com/smob/-/smob-1.4.1.tgz#66270e7df6a7527664816c5b577a23f17ba6f5b5"
-  integrity sha512-9LK+E7Hv5R9u4g4C3p+jjLstaLe11MDsL21UpYaCNmapvMkYhqCV4A/f/3gyH8QjMyh6l68q9xC85vihY9ahMQ==
-
 source-map-js@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/source-map-js/-/source-map-js-1.0.2.tgz#adbc361d9c62df380125e7f161f71c826f1e490c"
   integrity sha512-R0XvVJ9WusLiqTCEiGCmICCMplcCkIwwR11mOSD9CR5u+IXYdiseeEuXCVAjS54zqwkLcPNnmU4OeJ6tUrWhDw==
 
-source-map-support@~0.5.20:
-  version "0.5.21"
-  resolved "https://registry.yarnpkg.com/source-map-support/-/source-map-support-0.5.21.tgz#04fe7c7f9e1ed2d662233c28cb2b35b9f63f6e4f"
-  integrity sha512-uBHU3L3czsIyYXKX88fdrGovxdSCoTGDRZ6SYXtSRxLZUzHg5P/66Ht6uoUlHu9EZod+inXhKo3qQgwXUT/y1w==
-  dependencies:
-    buffer-from "^1.0.0"
-    source-map "^0.6.0"
-
-source-map@^0.6.0, source-map@^0.6.1:
+source-map@^0.6.1:
   version "0.6.1"
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.6.1.tgz#74722af32e9614e9c287a8d0bbde48b5e2f1a263"
   integrity sha512-UjgapumWlbMhkBgzT7Ykc5YXUT46F0iKu8SGXq0bcwP5dz/h0Plj6enJqjz1Zbq2l5WaqYnrVbwWOWMyF3F47g==
@@ -4559,16 +4500,6 @@ synckit@^0.8.5:
     "@pkgr/utils" "^2.4.2"
     tslib "^2.6.2"
 
-terser@^5.17.4:
-  version "5.26.0"
-  resolved "https://registry.yarnpkg.com/terser/-/terser-5.26.0.tgz#ee9f05d929f4189a9c28a0feb889d96d50126fe1"
-  integrity sha512-dytTGoE2oHgbNV9nTzgBEPaqAWvcJNl66VZ0BkJqlvp71IjO8CxdBx/ykCNb47cLnCmCvRZ6ZR0tLkqvZCdVBQ==
-  dependencies:
-    "@jridgewell/source-map" "^0.3.3"
-    acorn "^8.8.2"
-    commander "^2.20.0"
-    source-map-support "~0.5.20"
-
 test-exclude@^6.0.0:
   version "6.0.0"
   resolved "https://registry.yarnpkg.com/test-exclude/-/test-exclude-6.0.0.tgz#04a8698661d805ea6fa293b6cb9e63ac044ef15e"