diff --git a/.dev/tests/cypress/helpers.js b/.dev/tests/cypress/helpers.js
index 94f485ba607..a13da295d7a 100644
--- a/.dev/tests/cypress/helpers.js
+++ b/.dev/tests/cypress/helpers.js
@@ -2,7 +2,7 @@
  * Returns true if styles tab exists false otherwise.
  */
 export function selectStylesTabIfExists() {
-	cy.get( '.edit-post-sidebar' ).find( 'button[aria-label="Styles"]' ).click();
+	cy.get( sidebarClass() ).find( 'button[aria-label="Styles"]' ).click();
 }
 
 /**
@@ -172,7 +172,11 @@ export function addNewGroupToPost() {
  * From inside the WordPress editor open the CoBlocks Gutenberg editor panel
  */
 export function savePage() {
-	cy.get( '.edit-post-header__settings button.is-primary' ).click();
+	if ( isWP66AtLeast() ) {
+		cy.get( '.editor-header__settings button.is-primary' ).click();
+	} else {
+		cy.get( '.edit-post-header__settings button.is-primary' ).click();
+	}
 
 	cy.get( '.components-editor-notices__snackbar', { timeout: 120000 } ).should( 'not.be.empty' );
 
@@ -263,7 +267,7 @@ export function getBlockSlug() {
 export function setBlockStyle( style ) {
 	openSettingsPanel( RegExp( 'styles', 'i' ) );
 
-	cy.get( '.edit-post-sidebar [class*="editor-block-styles"]' )
+	cy.get( sidebarClass() + ' [class*="editor-block-styles"]' )
 		.contains( RegExp( style, 'i' ) )
 		.click();
 }
@@ -276,7 +280,7 @@ export function setBlockStyle( style ) {
 export function setNewBlockStyle( style ) {
 	selectStylesTabIfExists();
 
-	cy.get( '.edit-post-sidebar [class*="editor-block-styles"]' )
+	cy.get( sidebarClass() + ' [class*="editor-block-styles"]' )
 		.contains( RegExp( style, 'i' ) )
 		.click();
 }
@@ -350,7 +354,7 @@ export function setBlockAlignment( alignment ) {
 export function setInputValue( panelName, settingName, value, ignoreCase = true ) {
 	openSettingsPanel( ignoreCase ? RegExp( panelName, 'i' ) : panelName );
 
-	cy.get( '.edit-post-sidebar' )
+	cy.get( sidebarClass() )
 		.contains( ignoreCase ? RegExp( settingName, 'i' ) : settingName ).not( '.block-editor-block-card__description' )
 		.then( ( $settingSection ) => {
 			cy.get( Cypress.$( $settingSection ).parent() )
@@ -557,7 +561,7 @@ export function addCustomBlockClass( classes, blockID = '' ) {
 		}
 	} );
 
-	cy.get( 'div.edit-post-sidebar' )
+	cy.get( 'div' + sidebarClass() )
 		.contains( /Additional CSS/i )
 		.next( 'input' )
 		.then( ( $inputElem ) => {
@@ -612,15 +616,14 @@ export function isNotWPLocalEnv() {
 	return Cypress.env( 'testURL' ) !== 'http://localhost:8889';
 }
 
-// A condition to determine if we are testing on WordPress 6.4+
-export function isWP64AtLeast() {
-	return Cypress.$( "[class*='branch-6-4']" ).length > 0 || Cypress.$( "[class*='branch-6-5']" ).length > 0;
-}
-
 export function isWP65AtLeast() {
 	return Cypress.$( "[class*='branch-6-5']" ).length > 0 || Cypress.$( "[class*='branch-6-6']" ).length > 0;
 }
 
+export function isWP66AtLeast() {
+	return Cypress.$( "[class*='branch-6-6']" ).length > 0 || Cypress.$( "[class*='branch-6-7']" ).length > 0;
+}
+
 function getIframeDocument( containerClass ) {
 	return cy.get( containerClass + ' iframe' ).its( '0.contentDocument' ).should( 'exist' );
 }
@@ -631,3 +634,7 @@ export function getIframeBody( containerClass ) {
 		// chaining more Cypress commands, like ".find(...)"
 		.then( cy.wrap );
 }
+
+export const sidebarClass = () => {
+	return isWP66AtLeast() ? '.editor-sidebar__panel' : '.edit-post-sidebar';
+};
diff --git a/.github/workflows/test-e2e.yml b/.github/workflows/test-e2e.yml
index e12541a9cea..ba65fa7e6b7 100644
--- a/.github/workflows/test-e2e.yml
+++ b/.github/workflows/test-e2e.yml
@@ -22,9 +22,9 @@ jobs:
       fail-fast: false
       matrix:
         wp: # Test against Prev-Prev Major, Prev-Major, and current Major release versions.
-          - "6.3"
           - "6.4"
           - "6.5"
+          - "6.6"
         theme:
           - "https://downloads.wordpress.org/theme/go.zip"
           - "" # Default theme is TwentyTwentyThree
diff --git a/.github/workflows/test-php.yml b/.github/workflows/test-php.yml
index 86f9553de50..b761b29e1d9 100644
--- a/.github/workflows/test-php.yml
+++ b/.github/workflows/test-php.yml
@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         php: ['7.4','8.3']
-        wp: ['6.4'] # TODO: Add 6.6 when released
+        wp: ['6.6']
     name: PHP Unit ${{ matrix.php }} | WP Version ${{ matrix.wp }}
     uses: ./.github/workflows/test-php-unit.yml
     with:
diff --git a/includes/block-migrate/loader.php b/includes/block-migrate/loader.php
index ad5d4d6b1b6..d783bce4e97 100644
--- a/includes/block-migrate/loader.php
+++ b/includes/block-migrate/loader.php
@@ -35,6 +35,11 @@ function( WP_Post &$post ) {
 			return;
 		}
 
+		// Bail if DOMDocument is not available.
+		if ( ! class_exists( 'DOMDocument' ) ) {
+			return;
+		}
+
 		// Parse the blocks so we can search them in a standard way.
 		$parsed_blocks = parse_blocks( $post->post_content );
 
diff --git a/package.json b/package.json
index 5aed1d7d896..d3abbc6a5e8 100644
--- a/package.json
+++ b/package.json
@@ -119,6 +119,7 @@
 		"@wordpress/editor": "^13.21.0",
 		"@wordpress/element": "^5.21.0",
 		"@wordpress/env": "^10.1.0",
+		"@wordpress/escape-html": "^3.4.0",
 		"@wordpress/eslint-plugin": "^17.1.0",
 		"@wordpress/hooks": "^3.44.0",
 		"@wordpress/i18n": "^4.44.0",
diff --git a/src/blocks/features/test/features.cypress.js b/src/blocks/features/test/features.cypress.js
index ef94fdb6690..13cad3e6af9 100644
--- a/src/blocks/features/test/features.cypress.js
+++ b/src/blocks/features/test/features.cypress.js
@@ -43,15 +43,15 @@ describe( 'Test CoBlocks Features Block', function() {
 
 		cy.get( '.wp-block-coblocks-feature' ).should( 'have.length', 2 );
 
-		cy.get( '.edit-post-sidebar' ).find( 'input[aria-label="Columns"][type="number"]' ).focus().type( '{selectall}' ).type( 1 );
+		cy.get( helpers.sidebarClass() ).find( 'input[aria-label="Columns"][type="number"]' ).focus().type( '{selectall}' ).type( 1 );
 
 		cy.get( '.wp-block-coblocks-feature' ).should( 'have.length', 2 ); // Children should never decrease with column count
 
-		cy.get( '.edit-post-sidebar' ).find( 'input[aria-label="Columns"][type="number"]' ).focus().type( '{selectall}' ).type( 3 );
+		cy.get( helpers.sidebarClass() ).find( 'input[aria-label="Columns"][type="number"]' ).focus().type( '{selectall}' ).type( 3 );
 
 		cy.get( '.wp-block-coblocks-feature' ).should( 'have.length', 3 );
 
-		cy.get( '.edit-post-sidebar' ).find( 'input[aria-label="Columns"][type="number"]' ).focus().type( '{selectall}' ).type( 4 );
+		cy.get( helpers.sidebarClass() ).find( 'input[aria-label="Columns"][type="number"]' ).focus().type( '{selectall}' ).type( 4 );
 
 		cy.get( '.wp-block-coblocks-feature' ).should( 'have.length', 4 );
 
diff --git a/src/blocks/form/test/form.cypress.js b/src/blocks/form/test/form.cypress.js
index b678917ce2d..a4c8d958cd5 100644
--- a/src/blocks/form/test/form.cypress.js
+++ b/src/blocks/form/test/form.cypress.js
@@ -401,7 +401,7 @@ describe( 'Test CoBlocks Form Block', function() {
 		cy.get( '[data-type="coblocks/form"]' )
 			.click( { force: true } );
 
-		cy.get( 'div.edit-post-sidebar' )
+		cy.get( 'div' + helpers.sidebarClass() )
 			.contains( /Subject/i )
 			.next( 'input' )
 			.then( ( $inputElem ) => {
@@ -479,7 +479,7 @@ describe( 'Test CoBlocks Form Block', function() {
 		cy.get( '[data-type="coblocks/form"]' )
 			.click( { force: true } );
 
-		cy.get( 'div.edit-post-sidebar' )
+		cy.get( 'div' + helpers.sidebarClass() )
 			.contains( /Success Message/i )
 			.next( 'textarea' )
 			.then( ( $inputElem ) => {
diff --git a/src/blocks/gif/test/gif.cypress.js b/src/blocks/gif/test/gif.cypress.js
index 6dea73bcc8e..57eff712883 100644
--- a/src/blocks/gif/test/gif.cypress.js
+++ b/src/blocks/gif/test/gif.cypress.js
@@ -42,7 +42,7 @@ describe( 'Test CoBlocks Gif Block', function() {
 
 		cy.get( '.wp-block-coblocks-gif' ).find( 'img' ).should( 'have.length', 1 );
 
-		cy.get( '.edit-post-sidebar' ).contains( /Alt text/ ).parent().find( 'textarea' ).type( gifText );
+		cy.get( helpers.sidebarClass() ).contains( /Alt text/ ).parent().find( 'textarea' ).type( gifText );
 
 		helpers.savePage();
 
diff --git a/src/blocks/hero/test/hero.cypress.js b/src/blocks/hero/test/hero.cypress.js
index 1b593faf6fe..f09564c2581 100644
--- a/src/blocks/hero/test/hero.cypress.js
+++ b/src/blocks/hero/test/hero.cypress.js
@@ -75,7 +75,7 @@ describe( 'Test CoBlocks Hero Block', function() {
 
 		cy.get( '.wp-block-coblocks-hero' ).find( '.is-fullscreen' ).should( 'exist' );
 
-		cy.get( '.edit-post-sidebar' ).find( 'div[aria-label="Select layout"]' ).children().each( ( $layoutButton ) => {
+		cy.get( helpers.sidebarClass() ).find( 'div[aria-label="Select layout"]' ).children().each( ( $layoutButton ) => {
 			cy.get( $layoutButton ).click();
 		} );
 
diff --git a/src/blocks/post-carousel/post-item.js b/src/blocks/post-carousel/post-item.js
index 4e7cee920dc..aeca2fe43c8 100644
--- a/src/blocks/post-carousel/post-item.js
+++ b/src/blocks/post-carousel/post-item.js
@@ -13,6 +13,7 @@ import {
 } from '@wordpress/components';
 import { PlainText } from '@wordpress/block-editor';
 import { RawHTML } from '@wordpress/element';
+import { escapeHTML } from '@wordpress/escape-html';
 import { withSelect } from '@wordpress/data';
 // Disable reason: We choose to use unsafe APIs in our codebase.
 // eslint-disable-next-line @wordpress/no-unsafe-wp-apis
@@ -78,7 +79,7 @@ const PostItem = ( {
 					<RawHTML
 						key="html"
 					>
-						{ excerpt.trim().split( ' ', excerptLength ).join( ' ' ) }
+						{ escapeHTML( excerpt.trim().split( ' ', excerptLength ).join( ' ' ) ) }
 					</RawHTML>
 				</div>
 				}
diff --git a/src/blocks/post-carousel/test/post-carousel.cypress.js b/src/blocks/post-carousel/test/post-carousel.cypress.js
index 1054ad0a635..e1b958840a5 100644
--- a/src/blocks/post-carousel/test/post-carousel.cypress.js
+++ b/src/blocks/post-carousel/test/post-carousel.cypress.js
@@ -57,9 +57,9 @@ describe( 'Test CoBlocks Post Carousel Block', function() {
 	it( 'Test the post-carousel block custom classes.', function() {
 		helpers.addBlockToPost( 'coblocks/post-carousel', true );
 
-		cy.get( '.edit-post-sidebar' ).contains( /post carousel settings/i ).click( { force: true } );
+		cy.get( helpers.sidebarClass() ).contains( /post carousel settings/i ).click( { force: true } );
 
-		cy.get( '.edit-post-sidebar' ).contains( /feed settings/i ).click( { force: true } );
+		cy.get( helpers.sidebarClass() ).contains( /feed settings/i ).click( { force: true } );
 
 		helpers.addCustomBlockClass( 'my-custom-class', 'post-carousel' );
 
diff --git a/src/blocks/posts/edit.js b/src/blocks/posts/edit.js
index 9ba6c6dcafa..abf08c9691e 100755
--- a/src/blocks/posts/edit.js
+++ b/src/blocks/posts/edit.js
@@ -13,6 +13,7 @@ import apiFetch from '@wordpress/api-fetch';
 import { __ } from '@wordpress/i18n';
 import { compose, usePrevious } from '@wordpress/compose';
 import { lazy, RawHTML, useState, useEffect, useRef } from '@wordpress/element';
+import { escapeHTML } from '@wordpress/escape-html';
 import { addQueryArgs } from '@wordpress/url';
 // Disable reason: We choose to use unsafe APIs in our codebase.
 // eslint-disable-next-line @wordpress/no-unsafe-wp-apis
@@ -435,8 +436,8 @@ const PostsEdit = ( props ) => {
 														key="html"
 													>
 														{ excerptLength < excerpt.trim().split( ' ' ).length
-															? excerpt.trim().split( ' ', excerptLength ).join( ' ' ) + '…'
-															: excerpt.trim().split( ' ', excerptLength ).join( ' ' ) }
+															? escapeHTML( excerpt.trim().split( ' ', excerptLength ).join( ' ' ) ) + '…'
+															: escapeHTML( excerpt.trim().split( ' ', excerptLength ).join( ' ' ) ) }
 													</RawHTML>
 												</div>
 											}
diff --git a/src/blocks/posts/test/posts.cypress.js b/src/blocks/posts/test/posts.cypress.js
index 3b543df6e64..9054ce15520 100644
--- a/src/blocks/posts/test/posts.cypress.js
+++ b/src/blocks/posts/test/posts.cypress.js
@@ -74,9 +74,9 @@ describe( 'Test CoBlocks Posts Block', function() {
 	it( 'Test posts block custom classes.', function() {
 		helpers.addBlockToPost( 'coblocks/posts', true );
 
-		cy.get( '.edit-post-sidebar' ).contains( /posts settings/i ).click( { force: true } );
+		cy.get( helpers.sidebarClass() ).contains( /posts settings/i ).click( { force: true } );
 
-		cy.get( '.edit-post-sidebar' ).contains( /feed settings/i ).click( { force: true } );
+		cy.get( helpers.sidebarClass() ).contains( /feed settings/i ).click( { force: true } );
 
 		helpers.addCustomBlockClass( 'my-custom-class', 'posts' );
 
diff --git a/src/blocks/pricing-table/pricing-table-item/test/pricing-table-item.cypress.js b/src/blocks/pricing-table/pricing-table-item/test/pricing-table-item.cypress.js
index c05a79b0d90..8a765c451a3 100644
--- a/src/blocks/pricing-table/pricing-table-item/test/pricing-table-item.cypress.js
+++ b/src/blocks/pricing-table/pricing-table-item/test/pricing-table-item.cypress.js
@@ -71,11 +71,7 @@ describe( 'Test CoBlocks Pricing Table Item Block', function() {
 
 		featuresText = ' ' + featuresText;
 
-		if ( helpers.isWP64AtLeast() ) {
-			firstTableItem().find( '.wp-block-coblocks-pricing-table-item__features' ).should( 'have.text', featuresText );
-		} else {
-			firstTableItem().find( '.wp-block-coblocks-pricing-table-item__features > li' ).should( 'have.text', featuresText );
-		}
+		firstTableItem().find( '.wp-block-coblocks-pricing-table-item__features' ).should( 'have.text', featuresText );
 
 		firstTableItem().find( '.wp-block-button' ).should( 'have.text', buttonText );
 	} );
diff --git a/src/blocks/row/test/row.cypress.js b/src/blocks/row/test/row.cypress.js
index 9e564e554a5..de2137f6032 100644
--- a/src/blocks/row/test/row.cypress.js
+++ b/src/blocks/row/test/row.cypress.js
@@ -104,7 +104,7 @@ describe( 'Test CoBlocks Row Block', function() {
 
 		cy.get( '.wp-block-coblocks-row' ).click( { force: true } );
 
-		cy.get( '.edit-post-sidebar' ).contains( /row settings/i ).click();
+		cy.get( helpers.sidebarClass() ).contains( /row settings/i ).click();
 
 		helpers.addCustomBlockClass( 'my-custom-class', 'row' );
 
diff --git a/src/blocks/services/service/test/service.cypress.js b/src/blocks/services/service/test/service.cypress.js
index 207d2fca131..0edae5ad2aa 100644
--- a/src/blocks/services/service/test/service.cypress.js
+++ b/src/blocks/services/service/test/service.cypress.js
@@ -40,7 +40,7 @@ describe( 'Test CoBlocks Service Block', function() {
 			}
 		} );
 
-		cy.get( 'div.edit-post-sidebar' )
+		cy.get( 'div' + helpers.sidebarClass() )
 			.contains( /Additional CSS/i )
 			.next( 'input' )
 			.then( ( $inputElem ) => {
@@ -56,7 +56,7 @@ describe( 'Test CoBlocks Service Block', function() {
 			}
 		} );
 
-		cy.get( 'div.edit-post-sidebar' )
+		cy.get( 'div' + helpers.sidebarClass() )
 			.contains( /Additional CSS/i )
 			.next( 'input' )
 			.then( ( $inputElem ) => {
diff --git a/src/blocks/services/test/services.cypress.js b/src/blocks/services/test/services.cypress.js
index 7c33bfbfd7c..9ed90841ffd 100644
--- a/src/blocks/services/test/services.cypress.js
+++ b/src/blocks/services/test/services.cypress.js
@@ -73,7 +73,8 @@ describe( 'Test CoBlocks Services Block', function() {
 	it( 'Test service block has the proper arrow orientation.', function() {
 		helpers.addBlockToPost( 'coblocks/services', true );
 
-		cy.get( '.edit-post-visual-editor [data-type="coblocks/service"]:first-child' ).click();
+		// helpers.selectBlock('service');
+		cy.get( '.edit-post-visual-editor [data-type="coblocks/service"]:first-child' ).focus();
 		cy.get( 'div.block-editor-block-mover' ).should( 'have.class', 'is-horizontal' );
 
 		// Select parent block
@@ -81,7 +82,7 @@ describe( 'Test CoBlocks Services Block', function() {
 
 		helpers.setInputValue( 'Services settings', 'Columns', 1, false );
 
-		cy.get( '.edit-post-visual-editor [data-type="coblocks/service"]:first-child' ).click();
+		cy.get( '.edit-post-visual-editor [data-type="coblocks/service"]:first-child' ).focus();
 		cy.get( 'div.block-editor-block-mover' ).should( 'not.have.class', 'is-horizontal' );
 
 		helpers.savePage();
diff --git a/src/blocks/shape-divider/test/shape-divider.cypress.js b/src/blocks/shape-divider/test/shape-divider.cypress.js
index 33f15468f2c..ea84133e752 100644
--- a/src/blocks/shape-divider/test/shape-divider.cypress.js
+++ b/src/blocks/shape-divider/test/shape-divider.cypress.js
@@ -60,7 +60,7 @@ describe( 'Test CoBlocks Shape Divider Block', function() {
 
 		helpers.openSettingsPanel( 'Divider settings' );
 
-		cy.get( '.edit-post-sidebar' )
+		cy.get( helpers.sidebarClass() )
 			.contains( 'Shape height' ).not( '.block-editor-block-card__description' )
 			.then( ( $settingSection ) => {
 				cy.get( Cypress.$( $settingSection ).parent().parent() )
@@ -69,7 +69,7 @@ describe( 'Test CoBlocks Shape Divider Block', function() {
 					.type( `{selectall}${ shapeHeight }` );
 			} );
 
-		cy.get( '.edit-post-sidebar' )
+		cy.get( helpers.sidebarClass() )
 			.contains( 'Background height' ).not( '.block-editor-block-card__description' )
 			.then( ( $settingSection ) => {
 				cy.get( Cypress.$( $settingSection ).parent().parent() )
diff --git a/yarn.lock b/yarn.lock
index 678525c1eca..de8e133b53b 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4172,6 +4172,13 @@
   dependencies:
     "@babel/runtime" "^7.16.0"
 
+"@wordpress/escape-html@^3.4.0":
+  version "3.4.0"
+  resolved "https://registry.yarnpkg.com/@wordpress/escape-html/-/escape-html-3.4.0.tgz#ec625d409b018ff68d6081c66586fd420f74e122"
+  integrity sha512-KcUv+s0J/LEZEEvd+E3IkNCeW8wde0TjO+1HrcfvqI8Rfuc0zOAZeS/6ZqIeX0m/mhQ0xS2Y3e8hsnU+wAG6Mw==
+  dependencies:
+    "@babel/runtime" "^7.16.0"
+
 "@wordpress/eslint-plugin@^12.7.0":
   version "12.9.0"
   resolved "https://registry.yarnpkg.com/@wordpress/eslint-plugin/-/eslint-plugin-12.9.0.tgz#c49f0a523c8c72ade28c2b86a975668832b22938"