diff --git a/amp.php b/amp.php
index c2e988c0e58..42b16471322 100644
--- a/amp.php
+++ b/amp.php
@@ -64,6 +64,11 @@
 			'DOMXPath',
 		),
 	),
+	'filter' => array(
+		'functions' => array(
+			'filter_var',
+		),
+	),
 	// Required by PHP-CSS-Parser.
 	'iconv'  => array(
 		'functions' => array( 'iconv' ),
diff --git a/composer.json b/composer.json
index 45d6e89d3da..e94ed3094ff 100644
--- a/composer.json
+++ b/composer.json
@@ -9,11 +9,12 @@
     "ext-curl": "*",
     "ext-date": "*",
     "ext-dom": "*",
+    "ext-filter": "*",
     "ext-iconv": "*",
     "ext-json": "*",
     "ext-libxml": "*",
     "ext-spl": "*",
-    "ampproject/amp-toolbox": "^0.3",
+    "ampproject/amp-toolbox": "dev-main",
     "cweagans/composer-patches": "1.7.0",
     "fasterimage/fasterimage": "1.5.0",
     "sabberworm/php-css-parser": "dev-master#bfdd976"
diff --git a/composer.lock b/composer.lock
index c2731c6a14a..d6e9c37e8e8 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,24 +4,25 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "8ce341eb95c49935f972bd22a8b30c43",
+    "content-hash": "d94392c0c59201d458d0f3139fa0b7fe",
     "packages": [
         {
             "name": "ampproject/amp-toolbox",
-            "version": "0.3.0",
+            "version": "dev-main",
             "source": {
                 "type": "git",
                 "url": "https://github.com/ampproject/amp-toolbox-php.git",
-                "reference": "227563fe216069b2f33a652f8524d344662ba2e7"
+                "reference": "90452d0ef26f60947c7baf9bad221b3b97ff4ca3"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/ampproject/amp-toolbox-php/zipball/227563fe216069b2f33a652f8524d344662ba2e7",
-                "reference": "227563fe216069b2f33a652f8524d344662ba2e7",
+                "url": "https://api.github.com/repos/ampproject/amp-toolbox-php/zipball/90452d0ef26f60947c7baf9bad221b3b97ff4ca3",
+                "reference": "90452d0ef26f60947c7baf9bad221b3b97ff4ca3",
                 "shasum": ""
             },
             "require": {
                 "ext-dom": "*",
+                "ext-filter": "*",
                 "ext-iconv": "*",
                 "ext-json": "*",
                 "ext-libxml": "*",
@@ -43,6 +44,9 @@
                 "ext-json": "Provides native implementation of json_encode()/json_decode().",
                 "ext-mbstring": "Used by Dom\\Document to convert encoding to UTF-8 if needed."
             },
+            "bin": [
+                "bin/amp"
+            ],
             "type": "library",
             "extra": {
                 "downloads": {
@@ -63,7 +67,7 @@
                 "Apache-2.0"
             ],
             "description": "A collection of AMP tools making it easier to publish and host AMP pages with PHP.",
-            "time": "2021-03-29T21:05:18+00:00"
+            "time": "2021-04-10T15:34:10+00:00"
         },
         {
             "name": "cweagans/composer-patches",
@@ -1120,16 +1124,16 @@
         },
         {
             "name": "guzzlehttp/psr7",
-            "version": "1.7.0",
+            "version": "1.8.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/guzzle/psr7.git",
-                "reference": "53330f47520498c0ae1f61f7e2c90f55690c06a3"
+                "reference": "35ea11d335fd638b5882ff1725228b3d35496ab1"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/guzzle/psr7/zipball/53330f47520498c0ae1f61f7e2c90f55690c06a3",
-                "reference": "53330f47520498c0ae1f61f7e2c90f55690c06a3",
+                "url": "https://api.github.com/repos/guzzle/psr7/zipball/35ea11d335fd638b5882ff1725228b3d35496ab1",
+                "reference": "35ea11d335fd638b5882ff1725228b3d35496ab1",
                 "shasum": ""
             },
             "require": {
@@ -1187,7 +1191,11 @@
                 "uri",
                 "url"
             ],
-            "time": "2020-09-30T07:37:11+00:00"
+            "support": {
+                "issues": "https://github.com/guzzle/psr7/issues",
+                "source": "https://github.com/guzzle/psr7/tree/1.8.1"
+            },
+            "time": "2021-03-21T16:25:00+00:00"
         },
         {
             "name": "mikey179/vfsstream",
@@ -1639,21 +1647,21 @@
         },
         {
             "name": "php-parallel-lint/php-parallel-lint",
-            "version": "v1.2.0",
+            "version": "v1.3.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/php-parallel-lint/PHP-Parallel-Lint.git",
-                "reference": "474f18bc6cc6aca61ca40bfab55139de614e51ca"
+                "reference": "772a954e5f119f6f5871d015b23eabed8cbdadfb"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/php-parallel-lint/PHP-Parallel-Lint/zipball/474f18bc6cc6aca61ca40bfab55139de614e51ca",
-                "reference": "474f18bc6cc6aca61ca40bfab55139de614e51ca",
+                "url": "https://api.github.com/repos/php-parallel-lint/PHP-Parallel-Lint/zipball/772a954e5f119f6f5871d015b23eabed8cbdadfb",
+                "reference": "772a954e5f119f6f5871d015b23eabed8cbdadfb",
                 "shasum": ""
             },
             "require": {
                 "ext-json": "*",
-                "php": ">=5.4.0"
+                "php": ">=5.3.0"
             },
             "replace": {
                 "grogy/php-parallel-lint": "*",
@@ -1662,7 +1670,7 @@
             "require-dev": {
                 "nette/tester": "^1.3 || ^2.0",
                 "php-parallel-lint/php-console-highlighter": "~0.3",
-                "squizlabs/php_codesniffer": "~3.0"
+                "squizlabs/php_codesniffer": "^3.5"
             },
             "suggest": {
                 "php-parallel-lint/php-console-highlighter": "Highlight syntax in code snippet"
@@ -1688,7 +1696,7 @@
             ],
             "description": "This tool check syntax of PHP files about 20x faster than serial check.",
             "homepage": "https://github.com/php-parallel-lint/PHP-Parallel-Lint",
-            "time": "2020-04-04T12:18:32+00:00"
+            "time": "2021-04-07T14:42:48+00:00"
         },
         {
             "name": "php-stubs/wordpress-stubs",
@@ -2779,12 +2787,12 @@
             "source": {
                 "type": "git",
                 "url": "https://github.com/Roave/SecurityAdvisories.git",
-                "reference": "fe6ef201f838f07770873731a99f359ebb64fa50"
+                "reference": "aa48fe959b0236eede9c51a38f47df2bb81ef137"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/Roave/SecurityAdvisories/zipball/fe6ef201f838f07770873731a99f359ebb64fa50",
-                "reference": "fe6ef201f838f07770873731a99f359ebb64fa50",
+                "url": "https://api.github.com/repos/Roave/SecurityAdvisories/zipball/aa48fe959b0236eede9c51a38f47df2bb81ef137",
+                "reference": "aa48fe959b0236eede9c51a38f47df2bb81ef137",
                 "shasum": ""
             },
             "conflict": {
@@ -2828,7 +2836,7 @@
                 "doctrine/doctrine-module": "<=0.7.1",
                 "doctrine/mongodb-odm": ">=1,<1.0.2",
                 "doctrine/mongodb-odm-bundle": ">=2,<3.0.1",
-                "doctrine/orm": ">=2,<2.4.8|>=2.5,<2.5.1",
+                "doctrine/orm": ">=2,<2.4.8|>=2.5,<2.5.1|>=2.8.3,<2.8.4",
                 "dolibarr/dolibarr": "<11.0.4",
                 "dompdf/dompdf": ">=0.6,<0.6.2",
                 "drupal/core": ">=7,<7.74|>=8,<8.8.11|>=8.9,<8.9.9|>=9,<9.0.8",
@@ -2843,18 +2851,19 @@
                 "ezsystems/ezplatform": ">=1.7,<1.7.9.1|>=1.13,<1.13.5.1|>=2.5,<2.5.4",
                 "ezsystems/ezplatform-admin-ui": ">=1.3,<1.3.5|>=1.4,<1.4.6",
                 "ezsystems/ezplatform-admin-ui-assets": ">=4,<4.2.1|>=5,<5.0.1|>=5.1,<5.1.1",
-                "ezsystems/ezplatform-kernel": ">=1,<1.0.2.1",
+                "ezsystems/ezplatform-kernel": "<=1.2.5|>=1.3,<=1.3.1",
                 "ezsystems/ezplatform-rest": ">=1.2,<=1.2.2|>=1.3,<=1.3.1",
                 "ezsystems/ezplatform-user": ">=1,<1.0.1",
-                "ezsystems/ezpublish-kernel": ">=5.3,<5.3.12.1|>=5.4,<5.4.14.2|>=6,<6.7.9.1|>=6.8,<=6.13.8|>=7,<7.2.4.1|>=7.3,<7.3.2.1|>=7.5,<=7.5.15",
+                "ezsystems/ezpublish-kernel": "<=6.13.8.1|>=7,<=7.5.15.1",
                 "ezsystems/ezpublish-legacy": ">=5.3,<5.3.12.6|>=5.4,<5.4.14.2|>=2011,<2017.12.7.3|>=2018.6,<2018.6.1.4|>=2018.9,<2018.9.1.3|>=2019.3,<2019.3.5.1",
                 "ezsystems/platform-ui-assets-bundle": ">=4.2,<4.2.3",
                 "ezsystems/repository-forms": ">=2.3,<2.3.2.1",
                 "ezyang/htmlpurifier": "<4.1.1",
-                "facade/ignition": "<=2.5.1,>=2.0|<=1.16.13",
+                "facade/ignition": "<1.16.14|>=2,<2.4.2|>=2.5,<2.5.2",
                 "firebase/php-jwt": "<2",
                 "flarum/sticky": ">=0.1-beta.14,<=0.1-beta.15",
                 "flarum/tags": "<=0.1-beta.13",
+                "fluidtypo3/vhs": "<5.1.1",
                 "fooman/tcpdf": "<6.2.22",
                 "fossar/tcpdf-parser": "<6.2.22",
                 "friendsofsymfony/oauth2-php": "<1.3",
@@ -2894,10 +2903,11 @@
                 "magento/magento1ee": ">=1,<1.14.4.3",
                 "magento/product-community-edition": ">=2,<2.2.10|>=2.3,<2.3.2-p.2",
                 "marcwillmann/turn": "<0.3.3",
-                "mautic/core": "<2.16.5|>=3,<3.2.4|= 2.13.1",
+                "mautic/core": "<3.3.2|= 2.13.1",
                 "mediawiki/core": ">=1.27,<1.27.6|>=1.29,<1.29.3|>=1.30,<1.30.2|>=1.31,<1.31.9|>=1.32,<1.32.6|>=1.32.99,<1.33.3|>=1.33.99,<1.34.3|>=1.34.99,<1.35",
                 "mittwald/typo3_forum": "<1.2.1",
                 "monolog/monolog": ">=1.8,<1.12",
+                "moodle/moodle": "<3.5.17|>=3.7,<3.7.9|>=3.8,<3.8.8|>=3.9,<3.9.5|>=3.10,<3.10.2",
                 "namshi/jose": "<2.2",
                 "nette/application": ">=2,<2.0.19|>=2.1,<2.1.13|>=2.2,<2.2.10|>=2.3,<2.3.14|>=2.4,<2.4.16|>=3,<3.0.6",
                 "nette/nette": ">=2,<2.0.19|>=2.1,<2.1.13",
@@ -2927,15 +2937,18 @@
                 "phpmyadmin/phpmyadmin": "<4.9.6|>=5,<5.0.3",
                 "phpoffice/phpexcel": "<1.8.2",
                 "phpoffice/phpspreadsheet": "<1.16",
+                "phpseclib/phpseclib": "<2.0.31|>=3,<3.0.7",
                 "phpunit/phpunit": ">=4.8.19,<4.8.28|>=5.0.10,<5.6.3",
                 "phpwhois/phpwhois": "<=4.2.5",
                 "phpxmlrpc/extras": "<0.6.1",
                 "pimcore/pimcore": "<6.8.8",
                 "pocketmine/pocketmine-mp": "<3.15.4",
+                "pressbooks/pressbooks": "<5.18",
                 "prestashop/autoupgrade": ">=4,<4.10.1",
                 "prestashop/contactform": ">1.0.1,<4.3",
                 "prestashop/gamification": "<2.3.2",
                 "prestashop/productcomments": ">=4,<4.2.1",
+                "prestashop/ps_emailsubscription": "<2.6.1",
                 "prestashop/ps_facetedsearch": "<3.4.1",
                 "privatebin/privatebin": "<1.2.2|>=1.3,<1.3.2",
                 "propel/propel": ">=2-alpha.1,<=2-alpha.7",
@@ -3024,7 +3037,9 @@
                 "truckersmp/phpwhois": "<=4.3.1",
                 "twig/twig": "<1.38|>=2,<2.7",
                 "typo3/cms": ">=6.2,<6.2.30|>=7,<7.6.32|>=8,<8.7.38|>=9,<9.5.25|>=10,<10.4.14|>=11,<11.1.1",
-                "typo3/cms-core": ">=8,<8.7.38|>=9,<9.5.25|>=10,<10.4.14|>=11,<11.1.1",
+                "typo3/cms-backend": ">=7,<=7.6.50|>=8,<=8.7.39|>=9,<=9.5.24|>=10,<=10.4.13|>=11,<=11.1",
+                "typo3/cms-core": ">=6.2,<=6.2.56|>=7,<=7.6.50|>=8,<=8.7.39|>=9,<9.5.25|>=10,<10.4.14|>=11,<11.1.1",
+                "typo3/cms-form": ">=8,<=8.7.39|>=9,<=9.5.24|>=10,<=10.4.13|>=11,<=11.1",
                 "typo3/flow": ">=1,<1.0.4|>=1.1,<1.1.1|>=2,<2.0.1|>=2.3,<2.3.16|>=3,<3.0.10|>=3.1,<3.1.7|>=3.2,<3.2.7|>=3.3,<3.3.5",
                 "typo3/neos": ">=1.1,<1.1.3|>=1.2,<1.2.13|>=2,<2.0.4",
                 "typo3/phar-stream-wrapper": ">=1,<2.1.1|>=3,<3.1.1",
@@ -3034,6 +3049,7 @@
                 "verot/class.upload.php": "<=1.0.3|>=2,<=2.0.4",
                 "vrana/adminer": "<4.7.9",
                 "wallabag/tcpdf": "<6.2.22",
+                "wikimedia/parsoid": "<0.12.2",
                 "willdurand/js-translation-bundle": "<2.1.1",
                 "yii2mod/yii2-cms": "<1.9.2",
                 "yiisoft/yii": ">=1.1.14,<1.1.15",
@@ -3099,7 +3115,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2021-03-16T14:08:12+00:00"
+            "time": "2021-04-09T08:01:23+00:00"
         },
         {
             "name": "sebastian/code-unit-reverse-lookup",
@@ -3670,16 +3686,16 @@
         },
         {
             "name": "squizlabs/php_codesniffer",
-            "version": "3.5.8",
+            "version": "3.6.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/squizlabs/PHP_CodeSniffer.git",
-                "reference": "9d583721a7157ee997f235f327de038e7ea6dac4"
+                "reference": "ffced0d2c8fa8e6cdc4d695a743271fab6c38625"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/squizlabs/PHP_CodeSniffer/zipball/9d583721a7157ee997f235f327de038e7ea6dac4",
-                "reference": "9d583721a7157ee997f235f327de038e7ea6dac4",
+                "url": "https://api.github.com/repos/squizlabs/PHP_CodeSniffer/zipball/ffced0d2c8fa8e6cdc4d695a743271fab6c38625",
+                "reference": "ffced0d2c8fa8e6cdc4d695a743271fab6c38625",
                 "shasum": ""
             },
             "require": {
@@ -3717,7 +3733,7 @@
                 "phpcs",
                 "standards"
             ],
-            "time": "2020-10-23T02:01:07+00:00"
+            "time": "2021-04-09T00:54:41+00:00"
         },
         {
             "name": "symfony/config",
@@ -5581,6 +5597,7 @@
     "aliases": [],
     "minimum-stability": "dev",
     "stability-flags": {
+        "ampproject/amp-toolbox": 20,
         "sabberworm/php-css-parser": 20,
         "roave/security-advisories": 20
     },
@@ -5591,6 +5608,7 @@
         "ext-curl": "*",
         "ext-date": "*",
         "ext-dom": "*",
+        "ext-filter": "*",
         "ext-iconv": "*",
         "ext-json": "*",
         "ext-libxml": "*",
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index e0b6b65d849..17ec016ceff 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -1388,7 +1388,7 @@ public static function filter_admin_bar_script_loader_tag( $tag, $handle ) {
 	 */
 	public static function ensure_required_markup( Document $dom, $script_handles = [] ) {
 		// Gather all links.
-		$links         = [
+		$links = [
 			Attribute::REL_PRECONNECT => [
 				// Include preconnect link for AMP CDN for browsers that don't support preload.
 				AMP_DOM_Utils::create_node(
@@ -1401,7 +1401,9 @@ public static function ensure_required_markup( Document $dom, $script_handles =
 				),
 			],
 		];
+
 		$link_elements = $dom->head->getElementsByTagName( Tag::LINK );
+
 		/**
 		 * Link element.
 		 *
@@ -1500,32 +1502,16 @@ public static function ensure_required_markup( Document $dom, $script_handles =
 			}
 		}
 
-		/* phpcs:ignore Squiz.PHP.CommentedOutCode.Found
-		 *
-		 * "2. Next, preload the AMP runtime v0.js <script> tag with <link as=script href=https://cdn.ampproject.org/v0.js rel=preload>.
-		 * The AMP runtime should start downloading as soon as possible because the AMP boilerplate hides the document via body { visibility:hidden }
-		 * until the AMP runtime has loaded. Preloading the AMP runtime tells the browser to download the script with a higher priority."
-		 * {@link https://amp.dev/documentation/guides-and-tutorials/optimize-and-measure/optimize_amp/ Optimize the AMP Runtime loading}
+		/*
+		 * "3. If your page includes render-delaying extensions (e.g., amp-experiment, amp-dynamic-css-classes, amp-story),
+		 * preload those extensions as they're required by the AMP runtime for rendering the page."
+		 * @TODO: Move into RewriteAmpUrls transformer, as that will support self-hosting as well.
 		 */
 		$prioritized_preloads = [];
 		if ( ! isset( $links[ Attribute::REL_PRELOAD ] ) ) {
 			$links[ Attribute::REL_PRELOAD ] = [];
 		}
 
-		$prioritized_preloads[] = AMP_DOM_Utils::create_node(
-			$dom,
-			Tag::LINK,
-			[
-				Attribute::REL  => Attribute::REL_PRELOAD,
-				Attribute::AS_  => RequestDestination::SCRIPT,
-				Attribute::HREF => $runtime_src,
-			]
-		);
-
-		/*
-		 * "3. If your page includes render-delaying extensions (e.g., amp-experiment, amp-dynamic-css-classes, amp-story),
-		 * preload those extensions as they're required by the AMP runtime for rendering the page."
-		 */
 		$amp_script_handles = array_keys( $amp_scripts );
 		foreach ( array_intersect( Amp::RENDER_DELAYING_EXTENSIONS, $amp_script_handles ) as $script_handle ) {
 			if ( ! in_array( $script_handle, Amp::RENDER_DELAYING_EXTENSIONS, true ) ) {
@@ -1991,6 +1977,8 @@ public static function prepare_response( $response, $args = [] ) {
 			}
 		}
 
+		self::ensure_required_markup( $dom, array_keys( $amp_scripts ) );
+
 		$enable_optimizer = array_key_exists( ConfigurationArgument::ENABLE_OPTIMIZER, $args )
 			? $args[ ConfigurationArgument::ENABLE_OPTIMIZER ]
 			: true;
@@ -2049,8 +2037,6 @@ static function( Optimizer\Error $error ) {
 			do_action( 'amp_server_timing_stop', 'amp_optimizer' );
 		}
 
-		self::ensure_required_markup( $dom, array_keys( $amp_scripts ) );
-
 		$can_serve = AMP_Validation_Manager::finalize_validation( $dom );
 
 		// Redirect to the non-AMP version if not on an AMP-first site.
@@ -2130,6 +2116,7 @@ private static function get_optimizer_configuration( $args ) {
 				[
 					Optimizer\Transformer\AmpRuntimeCss::class,
 					Optimizer\Transformer\PreloadHeroImage::class,
+					Optimizer\Transformer\RewriteAmpUrls::class,
 					Optimizer\Transformer\ServerSideRendering::class,
 					Optimizer\Transformer\TransformedIdentifier::class,
 				]
diff --git a/src/ConfigurationArgument.php b/src/ConfigurationArgument.php
index 4adb29b136d..83aeea81e9f 100644
--- a/src/ConfigurationArgument.php
+++ b/src/ConfigurationArgument.php
@@ -16,6 +16,7 @@
  */
 interface ConfigurationArgument {
 
+	const ENABLE_ESM       = 'enable_esm';
 	const ENABLE_OPTIMIZER = 'enable_optimizer';
 	const ENABLE_SSR       = 'enable_ssr';
 }
diff --git a/tests/php/test-class-amp-nav-menu-toggle-sanitizer.php b/tests/php/test-class-amp-nav-menu-toggle-sanitizer.php
index 836fc4470e9..75e53ced77c 100644
--- a/tests/php/test-class-amp-nav-menu-toggle-sanitizer.php
+++ b/tests/php/test-class-amp-nav-menu-toggle-sanitizer.php
@@ -35,7 +35,7 @@ public function data_converter() {
 			}
 			return ' data-amp-bind-class="&quot;' . $class . '&quot; + ( navMenuToggledOn ? &quot; ' . $toggle_class . '&quot; : \'\' )"';
 		};
-		$amp_get_toggle_attrs    = function( $class = '', $toggle_class = 'toggled-on' ) {
+		$amp_get_toggle_attrs    = function( $class = '', $toggle_class = 'toggled-on' ) { // phpcs:ignore Generic.Formatting.MultipleStatementAlignment.NotSameWarning -- Sniff has a bug.
 			return ' on="tap:AMP.setState({ navMenuToggledOn: ! navMenuToggledOn })" aria-expanded="false" data-amp-bind-aria-expanded="navMenuToggledOn ? \'true\' : \'false\'"' . ( ! empty( $toggle_class ) ? ' data-amp-bind-class="&quot;' . $class . '&quot; + ( navMenuToggledOn ? &quot; ' . $toggle_class . '&quot; : \'\' )"' : '' );
 		};
 
diff --git a/tests/php/test-class-amp-theme-support.php b/tests/php/test-class-amp-theme-support.php
index 37791f258e6..5c3adb16ba4 100644
--- a/tests/php/test-class-amp-theme-support.php
+++ b/tests/php/test-class-amp-theme-support.php
@@ -418,7 +418,7 @@ static function ( $script ) {
 		$this->assertStringContains( '<meta name="viewport" content="maximum-scale=1.0,width=device-width">', $sanitized_html );
 
 		// MathML script was added.
-		$this->assertStringContains( '<script type="text/javascript" src="https://cdn.ampproject.org/v0/amp-mathml-0.1.js" async custom-element="amp-mathml"></script>', $sanitized_html ); // phpcs:ignore WordPress.WP.EnqueuedResources.NonEnqueuedScript
+		$this->assertStringContains( 'https://cdn.ampproject.org/v0/amp-mathml-0.1.js', $sanitized_html ); // phpcs:ignore WordPress.WP.EnqueuedResources.NonEnqueuedScript
 	}
 
 	/**
@@ -1642,23 +1642,22 @@ static function ( $url ) {
 			'<html amp=""',
 			'<meta charset="' . Document\Encoding::AMP . '">',
 			'<meta name="viewport" content="width=device-width">',
-			'<meta name="generator" content="AMP Plugin',
-			'<title>',
+			'<link as="script" crossorigin="anonymous" href="https://cdn.ampproject.org/v0.mjs" rel="modulepreload">',
 			'<link rel="preconnect" href="https://cdn.ampproject.org">',
-			'<link rel="preconnect" href="https://fonts.gstatic.com/" crossorigin="">',
 			'<link rel="dns-prefetch" href="//cdn.ampproject.org">',
-			'<link rel="preload" as="script" href="https://cdn.ampproject.org/v0.js">',
 			'<link rel="preload" as="script" href="https://cdn.ampproject.org/v0/amp-dynamic-css-classes-0.1.js">',
 			'<link rel="preload" as="script" href="https://cdn.ampproject.org/v0/amp-experiment-0.1.js">',
-			'<script type="text/javascript" src="https://cdn.ampproject.org/v0.js" async></script>',
+			'<meta name="generator" content="AMP Plugin',
+			'<link rel="preconnect" href="https://fonts.gstatic.com/" crossorigin="">',
 
-			'<script async custom-element="amp-dynamic-css-classes" src="https://cdn.ampproject.org/v0/amp-dynamic-css-classes-0.1.js"></script>',
-			'<script src="https://cdn.ampproject.org/v0/amp-experiment-0.1.js" async="" custom-element="amp-experiment"></script>',
+			'<script type="module" src="https://cdn.ampproject.org/v0.mjs" async crossorigin="anonymous"></script>',
+			'<script async custom-element="amp-dynamic-css-classes" src="https://cdn.ampproject.org/v0/amp-dynamic-css-classes-0.1.mjs" type="module" crossorigin="anonymous"></script>',
+			'<script src="https://cdn.ampproject.org/v0/amp-experiment-0.1.mjs" async="" custom-element="amp-experiment" type="module" crossorigin="anonymous"></script>',
 
-			'#<script( type=[\'"]text/javascript[\'"])? src=[\'"]https\://cdn\.ampproject\.org/v0/amp-ad-0\.1\.js[\'"] async(=[\'"][\'"])? custom-element=[\'"]amp-ad[\'"]>\s*</script>#s',
-			'#<script src=[\'"]https\://cdn\.ampproject\.org/v0/amp-audio-0\.1\.js[\'"] async(=[\'"][\'"])? custom-element=[\'"]amp-audio[\'"]>\s*</script>#s',
-			'<script type="text/javascript" src="https://cdn.ampproject.org/v0/amp-list-0.1.js" async custom-element="amp-list"></script>',
-			'<script type="text/javascript" src="https://cdn.ampproject.org/v0/amp-mathml-0.1.js" async custom-element="amp-mathml"></script>',
+			'<script src="https://cdn.ampproject.org/v0/amp-ad-0.1.mjs" async="" custom-element="amp-ad" type="module" crossorigin="anonymous"></script>',
+			'<script src="https://cdn.ampproject.org/v0/amp-audio-0.1.mjs" async="" custom-element="amp-audio" type="module" crossorigin="anonymous"></script>',
+			'<script type="module" src="https://cdn.ampproject.org/v0/amp-list-0.1.mjs" async custom-element="amp-list" crossorigin="anonymous"></script>',
+			'<script type="module" src="https://cdn.ampproject.org/v0/amp-mathml-0.1.mjs" async custom-element="amp-mathml" crossorigin="anonymous"></script>',
 
 			'<link rel="icon" href="https://example.org/favicon.png" sizes="32x32">',
 			'<link rel="icon" href="https://example.org/favicon.png" sizes="192x192">',
@@ -1666,11 +1665,12 @@ static function ( $url ) {
 
 			'#<style amp-custom(="")?>.*?body\s*{\s*background:\s*black;?\s*}.*?</style>#s',
 
+			'<title>',
+			'<link rel="canonical" href="',
 			'<script type="application/ld+json">{"@context"',
 
 			'#<style amp-boilerplate(="")?>#',
 			'#<noscript><style amp-boilerplate(="")?>#',
-			'<link rel="canonical" href="',
 			'</head>',
 		];