diff --git a/.browserslistrc b/.browserslistrc
index f5926db66fca..f500a9360514 100644
--- a/.browserslistrc
+++ b/.browserslistrc
@@ -1,28 +1,25 @@
 [modern]
-# Support for dynamic import is the main litmus test for serving modern builds.
-# Although officially a ES2020 feature, browsers implemented it early, so this
-# enables all of ES2017 and some features in ES2018.
-supports es6-module-dynamic-import
-
-# Exclude Safari 11-12 because of a bug in tagged template literals
-# https://bugs.webkit.org/show_bug.cgi?id=190756
-# Note: Dropping version 11 also enables several more ES2018 features
-not Safari < 13
-not iOS < 13
-
-# Exclude KaiOS, QQ, and UC browsers due to lack of sufficient feature support data
-# Babel ignores these automatically, but we need here for Webpack to output ESM with dynamic imports
+# Modern builds target recent browsers supporting the latest features to minimize transpilation, polyfills, etc.
+# It is served to browsers meeting the following requirements:
+# - released in the last year + current alpha/beta versions
+# - Firefox extended support release (ESR)
+# - with global utilization at or above 0.5%
+# - must support dynamic import of ES modules
+# - exclude browsers no longer being maintained
+# - exclude KaiOS, QQ, and UC browsers due to lack of sufficient feature support data
+unreleased versions
+last 1 year
+Firefox ESR
+>= 0.5% and supports es6-module-dynamic-import
+not dead
 not KaiOS > 0
 not QQAndroid > 0
 not UCAndroid > 0
 
-# Exclude unsupported browsers
-not dead
-
 [legacy]
 # Legacy builds are served when modern requirements are not met and support browsers:
 # - released in the last 7 years + current alpha/beta versionss
-# - with global utilization above 0.05%
+# - with global utilization at or above 0.05%
 # The lattermost query ensures that support for popular old browsers is not dropped too early
 # (e.g. IE 11, Android 4.4, or Samsung 4).
 #
@@ -36,10 +33,10 @@ not dead
 # As of May 2023, only web sockets must be added to the query.
 unreleased versions
 last 7 years
-> 0.05% and supports websockets
+>= 0.05% and supports websockets
 
 [legacy-sw]
 # Same as legacy plus supports service workers
 unreleased versions
 last 7 years
-> 0.05% and supports websockets and supports serviceworkers
+>= 0.05% and supports websockets and supports serviceworkers
diff --git a/build-scripts/bundle.cjs b/build-scripts/bundle.cjs
index f74ddfeef33d..84e1490f995b 100644
--- a/build-scripts/bundle.cjs
+++ b/build-scripts/bundle.cjs
@@ -140,8 +140,14 @@ module.exports.babelOptions = ({
       "@babel/plugin-transform-runtime",
       { version: dependencies["@babel/runtime"] },
     ],
-    // Support  some proposals still in TC39 process
-    ["@babel/plugin-proposal-decorators", { decoratorsBeforeExport: true }],
+    // Transpile decorators (still in TC39 process)
+    // Modern browsers support class fields and private methods, but transform is required with the older decorator version dictated by Lit
+    [
+      "@babel/plugin-proposal-decorators",
+      { version: "2018-09", decoratorsBeforeExport: true },
+    ],
+    "@babel/plugin-transform-class-properties",
+    "@babel/plugin-transform-private-methods",
   ].filter(Boolean),
   exclude: [
     // \\ for Windows, / for Mac OS and Linux
diff --git a/build-scripts/gulp/entry-html.js b/build-scripts/gulp/entry-html.js
index dd6285c3103a..3afb7510393c 100644
--- a/build-scripts/gulp/entry-html.js
+++ b/build-scripts/gulp/entry-html.js
@@ -1,5 +1,6 @@
 // Tasks to generate entry HTML
 
+import { getUserAgentRegex } from "browserslist-useragent-regexp";
 import fs from "fs-extra";
 import gulp from "gulp";
 import { minify } from "html-minifier-terser";
@@ -17,6 +18,12 @@ const renderTemplate = (templateFile, data = {}) => {
     ...data,
     useRollup: env.useRollup(),
     useWDS: env.useWDS(),
+    modernRegex: getUserAgentRegex({
+      env: "modern",
+      allowHigherVersions: true,
+      mobileToDesktop: true,
+      throwOnMissing: true,
+    }).toString(),
     // Resolve any child/nested templates relative to the parent and pass the same data
     renderTemplate: (childTemplate) =>
       renderTemplate(
diff --git a/cast/src/html/faq.html.template b/cast/src/html/faq.html.template
index 80fc487bef21..ba22de72849d 100644
--- a/cast/src/html/faq.html.template
+++ b/cast/src/html/faq.html.template
@@ -36,13 +36,7 @@
   </head>
   <body>
     <%= renderTemplate("../../../src/html/_js_base.html.template") %>
-    <script>
-      <% for (const entry of latestEntryJS) { %>
-        import("<%= entry %>");
-      <% } %>
-      window.latestJS = true;
-    </script>
-    <%= renderTemplate("../../../src/html/_script_load_es5.html.template") %>
+    <%= renderTemplate("../../../src/html/_script_loader.html.template") %>
     <hc-layout subtitle="FAQ">
       <style>
         a {
diff --git a/cast/src/html/index.html.template b/cast/src/html/index.html.template
index 852a32bd7f91..18c45472f840 100644
--- a/cast/src/html/index.html.template
+++ b/cast/src/html/index.html.template
@@ -13,15 +13,9 @@
     <%= renderTemplate("_social_meta.html.template") %>
   </head>
   <body>
-    <%= renderTemplate("../../../src/html/_js_base.html.template") %>
     <hc-connect></hc-connect>
-    <script>
-      <% for (const entry of latestEntryJS) { %>
-        import("<%= entry %>");
-      <% } %>
-      window.latestJS = true;
-    </script>
-    <%= renderTemplate("../../../src/html/_script_load_es5.html.template") %>
+    <%= renderTemplate("../../../src/html/_js_base.html.template") %>
+    <%= renderTemplate("../../../src/html/_script_loader.html.template") %>
     <script>
     (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
     (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
diff --git a/cast/src/html/media.html.template b/cast/src/html/media.html.template
index 49633e084021..49acb9ba2346 100644
--- a/cast/src/html/media.html.template
+++ b/cast/src/html/media.html.template
@@ -16,14 +16,8 @@
     </style>
   </head>
   <body>
-    <%= renderTemplate("../../../src/html/_js_base.html.template") %>
     <cast-media-player></cast-media-player>
-    <script>
-      <% for (const entry of latestEntryJS) { %>
-        import("<%= entry %>");
-      <% } %>
-      window.latestJS = true;
-    </script>
-    <%= renderTemplate("../../../src/html/_script_load_es5.html.template") %>
+    <%= renderTemplate("../../../src/html/_js_base.html.template") %>
+    <%= renderTemplate("../../../src/html/_script_loader.html.template") %>
   </body>
 </html>
diff --git a/demo/src/html/index.html.template b/demo/src/html/index.html.template
index 6b044e44a355..4f4353d63363 100644
--- a/demo/src/html/index.html.template
+++ b/demo/src/html/index.html.template
@@ -83,15 +83,6 @@
     <ha-demo></ha-demo>
     <%= renderTemplate("../../../src/html/_js_base.html.template") %>
     <%= renderTemplate("../../../src/html/_preload_roboto.html.template") %>
-    <script>
-      // Safari 12 and below does not have a compliant ES2015 implementation of template literals, so we ship ES5
-      if (!isS11_12) {
-        <% for (const entry of latestEntryJS) { %>
-          import("<%= entry %>");
-        <% } %>
-        window.latestJS = true;
-      }
-    </script>
-    <%= renderTemplate("../../../src/html/_script_load_es5.html.template") %>
+    <%= renderTemplate("../../../src/html/_script_loader.html.template") %>
   </body>
 </html>
diff --git a/hassio/src/entrypoint.js.template b/hassio/src/entrypoint.js.template
index c1c4e5831ced..8cc7ba82fdc4 100644
--- a/hassio/src/entrypoint.js.template
+++ b/hassio/src/entrypoint.js.template
@@ -4,11 +4,7 @@
     el.src = src;
     document.body.appendChild(el);
   }
-  if (/.*Version\/(?:11|12)(?:\.\d+)*.*Safari\//.test(navigator.userAgent)) {
-    <% for (const entry of es5EntryJS) { %>
-      loadES5("<%= entry %>");
-    <% } %>
-  } else {
+  if (<%= modernRegex %>.test(navigator.userAgent)) {
     try {
         <% for (const entry of latestEntryJS) { %>
           new Function("import('<%= entry %>')")();
@@ -17,6 +13,10 @@
       <% for (const entry of es5EntryJS) { %>
         loadES5("<%= entry %>");
       <% } %>
+  } else {
+    <% for (const entry of es5EntryJS) { %>
+      loadES5("<%= entry %>");
+    <% } %>
   }
   }
 })();
diff --git a/package.json b/package.json
index cf2d567423ee..75b57f7d165a 100644
--- a/package.json
+++ b/package.json
@@ -191,6 +191,7 @@
     "@web/dev-server-rollup": "0.4.1",
     "babel-loader": "9.1.3",
     "babel-plugin-template-html-minifier": "4.1.0",
+    "browserslist-useragent-regexp": "4.1.3",
     "chai": "5.1.1",
     "del": "7.1.0",
     "eslint": "8.57.0",
diff --git a/src/html/_js_base.html.template b/src/html/_js_base.html.template
index 690cd0cd7aa9..aaa55cbfdcf0 100644
--- a/src/html/_js_base.html.template
+++ b/src/html/_js_base.html.template
@@ -16,8 +16,9 @@
   ) {
     _ls("/static/polyfills/webcomponents-bundle.js", true);
   }
-  var isS11_12 =
-    /(?:.*(?:iPhone|iPad).*OS (?:11|12)_\d)|(?:.*Version\/(?:11|12)(?:\.\d+)*.*Safari\/)/.test(
-      navigator.userAgent
-    );
+  // Modern browsers are detected primarily using the user agent string.
+  // A feature detection which roughly lines up with the modern targets is used
+  // as a fallback to guard against spoofs. It should be updated periodically.
+  var isModern = <%= modernRegex %>.test(navigator.userAgent) &&
+    "findLast" in Array.prototype;
 </script>
diff --git a/src/html/_script_load_es5.html.template b/src/html/_script_loader.html.template
similarity index 66%
rename from src/html/_script_load_es5.html.template
rename to src/html/_script_loader.html.template
index cb72d05e5ae7..5ea3f23ac476 100644
--- a/src/html/_script_load_es5.html.template
+++ b/src/html/_script_loader.html.template
@@ -1,3 +1,11 @@
+<script <% if (!useWDS) { %>crossorigin="use-credentials"<% } %>>
+  if (isModern) {
+    <% for (const entry of latestEntryJS) { %>
+      import("<%= entry %>");
+    <% } %>
+    window.latestJS = true;
+  }
+</script>
 <script>
   (function() {
     if (!window.latestJS) {
diff --git a/src/html/authorize.html.template b/src/html/authorize.html.template
index d4275d3381b1..9bf63eaa9464 100644
--- a/src/html/authorize.html.template
+++ b/src/html/authorize.html.template
@@ -52,18 +52,13 @@
     </div>
     <%= renderTemplate("_js_base.html.template") %>
     <%= renderTemplate("_preload_roboto.html.template") %>
+    <%= renderTemplate("_script_loader.html.template") %>
     <script crossorigin="use-credentials">
-      // Safari 12 and below does not have a compliant ES2015 implementation of template literals, so we ship ES5
-      if (!isS11_12) {
-        <% for (const entry of latestEntryJS) { %>
-          import("<%= entry %>");
-        <% } %>
-        window.latestJS = true;
+      if (window.latestJS) {
         window.providersPromise = fetch("/auth/providers", {
           credentials: "same-origin",
         });
       }
     </script>
-    <%= renderTemplate("_script_load_es5.html.template") %>
   </body>
 </html>
diff --git a/src/html/index.html.template b/src/html/index.html.template
index 7cfa93ea97b1..ef34659178e9 100644
--- a/src/html/index.html.template
+++ b/src/html/index.html.template
@@ -60,8 +60,7 @@
     <%= renderTemplate("_js_base.html.template") %>
     <%= renderTemplate("_preload_roboto.html.template") %>
     <script <% if (!useWDS) { %>crossorigin="use-credentials"<% } %>>
-      // Safari 12 and below does not have a compliant ES2015 implementation of template literals, so we ship ES5
-      if (!isS11_12) {
+      if (isModern) {
         <% for (const entry of latestEntryJS) { %>
           import("<%= entry %>");
         <% } %>
diff --git a/src/html/onboarding.html.template b/src/html/onboarding.html.template
index cac5129033cf..b19f68628c59 100644
--- a/src/html/onboarding.html.template
+++ b/src/html/onboarding.html.template
@@ -48,18 +48,13 @@
     </div>
     <%= renderTemplate("_js_base.html.template") %>
     <%= renderTemplate("_preload_roboto.html.template") %>
+    <%= renderTemplate("_script_loader.html.template") %>
     <script crossorigin="use-credentials">
-      // Safari 12 and below does not have a compliant ES2015 implementation of template literals, so we ship ES5
-      if (!isS11_12) {
-        <% for (const entry of latestEntryJS) { %>
-          import("<%= entry %>");
-        <% } %>
-        window.latestJS = true;
+      if (window.latestJS) {
         window.stepsPromise = fetch("/api/onboarding", {
           credentials: "same-origin",
         });
       }
     </script>
-    <%= renderTemplate("_script_load_es5.html.template") %>
   </body>
 </html>
diff --git a/yarn.lock b/yarn.lock
index 5f3af4cbd53d..561ef5f48372 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5605,6 +5605,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"argue-cli@npm:^2.1.0":
+  version: 2.1.0
+  resolution: "argue-cli@npm:2.1.0"
+  checksum: 10/0b300fa171895ad8856513a29320ff3db729637f0dcf0ff2e67a2991190d69d3eb08bc9318956e4bae42b0b6e2c8761b6929364c24640cadd12b5f04a4328a06
+  languageName: node
+  linkType: hard
+
 "aria-query@npm:^5.1.3":
   version: 5.3.0
   resolution: "aria-query@npm:5.3.0"
@@ -6051,6 +6058,24 @@ __metadata:
   languageName: node
   linkType: hard
 
+"browserslist-useragent-regexp@npm:4.1.3":
+  version: 4.1.3
+  resolution: "browserslist-useragent-regexp@npm:4.1.3"
+  dependencies:
+    argue-cli: "npm:^2.1.0"
+    easy-table: "npm:^1.2.0"
+    picocolors: "npm:^1.0.0"
+    regexp-tree: "npm:^0.1.24"
+    ua-regexes-lite: "npm:^1.2.1"
+  peerDependencies:
+    browserslist: ">=4.0.0"
+  bin:
+    bluare: dist/cli.js
+    browserslist-useragent-regexp: dist/cli.js
+  checksum: 10/f774feb5a766a0b2469c38b5a9f257213375ce106b7d50640ee529cea9c17b91da0f55c4f029fd1e075c8b846fa38cee6feb5620ea1a09f099bb0da61a7950eb
+  languageName: node
+  linkType: hard
+
 "browserslist@npm:^4.21.10, browserslist@npm:^4.23.0, browserslist@npm:^4.23.1":
   version: 4.23.2
   resolution: "browserslist@npm:4.23.2"
@@ -6950,7 +6975,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"defaults@npm:^1.0.4":
+"defaults@npm:^1.0.3, defaults@npm:^1.0.4":
   version: 1.0.4
   resolution: "defaults@npm:1.0.4"
   dependencies:
@@ -7173,6 +7198,19 @@ __metadata:
   languageName: node
   linkType: hard
 
+"easy-table@npm:^1.2.0":
+  version: 1.2.0
+  resolution: "easy-table@npm:1.2.0"
+  dependencies:
+    ansi-regex: "npm:^5.0.1"
+    wcwidth: "npm:^1.0.1"
+  dependenciesMeta:
+    wcwidth:
+      optional: true
+  checksum: 10/0d1be7cd9419cd1b56ca5a978646b3cff241ccd8cf95bdb2742f36854084b3aef2e9af6ec14142855aa80e4cab1f4baad0f610a99c77509f23676b8330730177
+  languageName: node
+  linkType: hard
+
 "ee-first@npm:1.1.1":
   version: 1.1.1
   resolution: "ee-first@npm:1.1.1"
@@ -9017,6 +9055,7 @@ __metadata:
     app-datepicker: "npm:5.1.1"
     babel-loader: "npm:9.1.3"
     babel-plugin-template-html-minifier: "npm:4.1.0"
+    browserslist-useragent-regexp: "npm:4.1.3"
     chai: "npm:5.1.1"
     chart.js: "npm:4.4.3"
     color-name: "npm:2.0.0"
@@ -12435,6 +12474,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"regexp-tree@npm:^0.1.24":
+  version: 0.1.27
+  resolution: "regexp-tree@npm:0.1.27"
+  bin:
+    regexp-tree: bin/regexp-tree
+  checksum: 10/08c70c8adb5a0d4af1061bf9eb05d3b6e1d948c433d6b7008e4b5eb12a49429c2d6ca8e9106339a432aa0d07bd6e1bccc638d8f4ab0d045f3adad22182b300a2
+  languageName: node
+  linkType: hard
+
 "regexp.prototype.flags@npm:^1.5.2":
   version: 1.5.2
   resolution: "regexp.prototype.flags@npm:1.5.2"
@@ -14326,6 +14374,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"ua-regexes-lite@npm:^1.2.1":
+  version: 1.2.1
+  resolution: "ua-regexes-lite@npm:1.2.1"
+  checksum: 10/3545a3bd0bedc5a66912b5ba8248a230f0f31f6f6446dd0fa83f7bf77a5e9b206122ab30a8c4b1150bb5ffe5407da8d3b7a557adfa542c0af6bae5ebd77dd703
+  languageName: node
+  linkType: hard
+
 "unbox-primitive@npm:^1.0.2":
   version: 1.0.2
   resolution: "unbox-primitive@npm:1.0.2"
@@ -14744,6 +14799,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"wcwidth@npm:^1.0.1":
+  version: 1.0.1
+  resolution: "wcwidth@npm:1.0.1"
+  dependencies:
+    defaults: "npm:^1.0.3"
+  checksum: 10/182ebac8ca0b96845fae6ef44afd4619df6987fe5cf552fdee8396d3daa1fb9b8ec5c6c69855acb7b3c1231571393bd1f0a4cdc4028d421575348f64bb0a8817
+  languageName: node
+  linkType: hard
+
 "web-component-analyzer@npm:^2.0.0":
   version: 2.0.0
   resolution: "web-component-analyzer@npm:2.0.0"