diff --git a/admin/importers/class-convertkit-admin-importer-aweber.php b/admin/importers/class-convertkit-admin-importer-aweber.php
index fd982f283..2df10614e 100644
--- a/admin/importers/class-convertkit-admin-importer-aweber.php
+++ b/admin/importers/class-convertkit-admin-importer-aweber.php
@@ -32,6 +32,24 @@ class ConvertKit_Admin_Importer_AWeber extends ConvertKit_Admin_Importer {
 	 */
 	public $shortcode_id_attribute = 'formid';
 
+	/**
+	 * Holds the block name for AWeber forms.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @var     string
+	 */
+	public $block_name = 'aweber-signupform-block/aweber-shortcode';
+
+	/**
+	 * Holds the ID attribute name for AWeber forms.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @var     string
+	 */
+	public $block_id_attribute = 'selectedShortCode';
+
 	/**
 	 * Returns an array of AWeber form IDs and titles.
 	 *
diff --git a/admin/importers/class-convertkit-admin-importer-mc4wp.php b/admin/importers/class-convertkit-admin-importer-mc4wp.php
index 84ed6e071..ad9239bb7 100644
--- a/admin/importers/class-convertkit-admin-importer-mc4wp.php
+++ b/admin/importers/class-convertkit-admin-importer-mc4wp.php
@@ -32,6 +32,24 @@ class ConvertKit_Admin_Importer_MC4WP extends ConvertKit_Admin_Importer {
 	 */
 	public $shortcode_id_attribute = 'id';
 
+	/**
+	 * Holds the block name for MC4WP forms.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @var     string
+	 */
+	public $block_name = 'mailchimp-for-wp/form';
+
+	/**
+	 * Holds the ID attribute name for MC4WP forms.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @var     string
+	 */
+	public $block_id_attribute = 'id';
+
 	/**
 	 * Returns an array of MC4WP form IDs and titles.
 	 *
diff --git a/admin/importers/class-convertkit-admin-importer.php b/admin/importers/class-convertkit-admin-importer.php
index c3f437f20..17e86d60c 100644
--- a/admin/importers/class-convertkit-admin-importer.php
+++ b/admin/importers/class-convertkit-admin-importer.php
@@ -24,7 +24,7 @@ abstract class ConvertKit_Admin_Importer {
 	public $shortcode_name = '';
 
 	/**
-	 * Holds the ID attribute name for the third party Form plugin.
+	 * Holds the shortcode ID attribute name for the third party Form plugin.
 	 *
 	 * @since   3.1.0
 	 *
@@ -32,6 +32,24 @@ abstract class ConvertKit_Admin_Importer {
 	 */
 	public $shortcode_id_attribute = '';
 
+	/**
+	 * Holds the block name for the third party Form plugin.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @var     string
+	 */
+	public $block_name = '';
+
+	/**
+	 * Holds the block ID attribute name for the third party Form plugin.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @var     string
+	 */
+	public $block_id_attribute = '';
+
 	/**
 	 * Returns an array of third party form IDs and titles.
 	 *
@@ -42,7 +60,7 @@ abstract class ConvertKit_Admin_Importer {
 	abstract public function get_forms();
 
 	/**
-	 * Returns an array of post IDs that contain the third partyform shortcode.
+	 * Returns an array of post IDs that contain the third party form block or shortcode.
 	 *
 	 * @since   3.1.5
 	 *
@@ -52,17 +70,21 @@ public function get_forms_in_posts() {
 
 		global $wpdb;
 
-		// Search post_content for the third party form shortcode and return array of post IDs.
+		// Search post_content for the third party form block or shortcode and return array of post IDs.
 		$results = $wpdb->get_col(
 			$wpdb->prepare(
 				"
             SELECT ID
             FROM {$wpdb->posts}
             WHERE post_status = %s
-            AND post_content LIKE %s
+            AND (
+				post_content LIKE %s
+				OR post_content LIKE %s
+			)
             ",
 				'publish',
-				'%[' . $this->shortcode_name . '%'
+				'%[' . $this->shortcode_name . '%',
+				'%<!-- wp:' . $this->block_name . '%'
 			)
 		);
 
@@ -101,8 +123,8 @@ public function has_forms_in_posts() {
 	 *
 	 * @since   3.1.0
 	 *
-	 * @param   int $third_party_form_id    The ID of the third party form.
-	 * @param   int $form_id                The ID of the Kit form.
+	 * @param   int $third_party_form_id    Third Party Form ID.
+	 * @param   int $form_id                Kit Form ID.
 	 */
 	public function replace_shortcodes_in_posts( $third_party_form_id, $form_id ) {
 
@@ -227,4 +249,146 @@ public function get_form_ids_from_content( $content ) {
 
 	}
 
+	/**
+	 * Replaces the third party form block with the Kit form block.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @param   int $third_party_form_id    Third Party Form ID.
+	 * @param   int $form_id                Kit Form ID.
+	 */
+	public function replace_blocks_in_posts( $third_party_form_id, $form_id ) {
+
+		// Get Posts that contain the third party Form Block.
+		$posts = $this->get_forms_in_posts();
+
+		// Bail if no Posts contain the third party Form Block.
+		if ( empty( $posts ) ) {
+			return;
+		}
+
+		// Iterate through Posts and replace the third party Form Block with the Kit Form Block.
+		foreach ( $posts as $post_id ) {
+			$this->replace_blocks_in_post( $post_id, $third_party_form_id, $form_id );
+		}
+
+	}
+
+	/**
+	 * Replaces the third party form block with the Kit form block in the given post.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @param   int $post_id                Post ID.
+	 * @param   int $third_party_form_id    Third Party Form ID.
+	 * @param   int $form_id                Kit Form ID.
+	 */
+	public function replace_blocks_in_post( $post_id, $third_party_form_id, $form_id ) {
+
+		// Get Post content.
+		$post_content = get_post_field( 'post_content', $post_id );
+
+		// Fetch Blocks from Content.
+		$blocks = parse_blocks( $post_content );
+
+		// If a single block was returned with blockName null, this content was not created using the block editor.
+		if ( count( $blocks ) === 1 && is_null( $blocks[0]['blockName'] ) ) {
+			return;
+		}
+
+		// Replace the third party Form Block with the Kit Form Block.
+		$post_content = $this->replace_blocks_in_content( $blocks, $third_party_form_id, $form_id );
+
+		// Double escape backslashes so that wp_update_post doesn't remove them.
+		// When content contains a single backslash (\), wp_update_post will strip it unless we double escape it (\\).
+		$post_content = str_replace( '\\', '\\\\', $post_content );
+
+		// Update the Post content.
+		wp_update_post(
+			array(
+				'ID'           => $post_id,
+				'post_content' => $post_content,
+			),
+			false,
+			false // Don't fire after action hooks.
+		);
+
+	}
+
+	/**
+	 * Replaces the third party form block with the Kit form block in the given string.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @param   array $blocks                 Blocks.
+	 * @param   int   $third_party_form_id    Third Party Form ID.
+	 * @param   int   $form_id                Kit Form ID.
+	 *
+	 * @return  string
+	 */
+	public function replace_blocks_in_content( $blocks, $third_party_form_id, $form_id ) {
+
+		// Recursively convert blocks.
+		$blocks = $this->recursively_convert_blocks( $blocks, $third_party_form_id, $form_id );
+
+		// Serialize blocks.
+		return serialize_blocks( $blocks );
+
+	}
+
+	/**
+	 * Recursively walks through an array of blocks and innerBlocks,
+	 * converting third party form blocks to Kit form blocks.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @param   array $blocks                 Blocks.
+	 * @param   int   $third_party_form_id    Third Party Form ID.
+	 * @param   int   $form_id                Kit Form ID.
+	 * @return  array
+	 */
+	private function recursively_convert_blocks( $blocks, $third_party_form_id, $form_id ) {
+
+		foreach ( $blocks as $index => $block ) {
+			// If this block has inner blocks, walk through the inner blocks.
+			if ( ! empty( $block['innerBlocks'] ) ) {
+				$blocks[ $index ]['innerBlocks'] = $this->recursively_convert_blocks( $block['innerBlocks'], $third_party_form_id, $form_id );
+			}
+
+			// Skip if a null block name.
+			if ( is_null( $block['blockName'] ) ) {
+				continue;
+			}
+
+			// Skip if not a third party form block.
+			if ( strpos( $block['blockName'], $this->block_name ) === false ) {
+				continue;
+			}
+
+			// Skip if the attribute doesn't exist i.e. the block was not configured.
+			if ( ! array_key_exists( $this->block_id_attribute, $block['attrs'] ) ) {
+				continue;
+			}
+
+			// Skip if the third party form ID doesn't exist within the third party form block's attribute.
+			if ( stripos( $block['attrs'][ $this->block_id_attribute ], (string) $third_party_form_id ) === false ) {
+				continue;
+			}
+
+			// Replace third party form block with Kit form block.
+			$blocks[ $index ] = array(
+				'blockName'    => 'convertkit/form',
+				'attrs'        => array(
+					'form' => (string) $form_id,
+				),
+				'innerBlocks'  => array(),
+				'innerHTML'    => '',
+				'innerContent' => array(),
+			);
+		}
+
+		return $blocks;
+
+	}
+
 }
diff --git a/admin/section/class-convertkit-admin-section-tools.php b/admin/section/class-convertkit-admin-section-tools.php
index fe62b0091..b13956391 100644
--- a/admin/section/class-convertkit-admin-section-tools.php
+++ b/admin/section/class-convertkit-admin-section-tools.php
@@ -345,6 +345,7 @@ private function maybe_migrate_aweber_configuration() {
 
 		// Iterate through the AWeber Form IDs and replace the shortcodes with the Kit Form Shortcodes.
 		foreach ( array_map( 'sanitize_text_field', wp_unslash( $_REQUEST['_wp_convertkit_integration_aweber_settings'] ) ) as $aweber_form_id => $kit_form_id ) {
+			$aweber->replace_blocks_in_posts( (int) $aweber_form_id, (int) $kit_form_id );
 			$aweber->replace_shortcodes_in_posts( (int) $aweber_form_id, (int) $kit_form_id );
 		}
 
@@ -380,6 +381,7 @@ private function maybe_migrate_mc4wp_configuration() {
 
 		// Iterate through the MC4WP Form IDs and replace the shortcodes with the Kit Form Shortcodes.
 		foreach ( array_map( 'sanitize_text_field', wp_unslash( $_REQUEST['_wp_convertkit_integration_mc4wp_settings'] ) ) as $mc4wp_form_id => $kit_form_id ) {
+			$mc4wp->replace_blocks_in_posts( (int) $mc4wp_form_id, (int) $kit_form_id );
 			$mc4wp->replace_shortcodes_in_posts( (int) $mc4wp_form_id, (int) $kit_form_id );
 		}
 
diff --git a/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterAweberCest.php b/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterAweberCest.php
index 27bdfca60..9c9046a67 100644
--- a/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterAweberCest.php
+++ b/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterAweberCest.php
@@ -31,7 +31,7 @@ public function _before(EndToEndTester $I)
 	 *
 	 * @param   EndToEndTester $I  Tester.
 	 */
-	public function testAWeberImport(EndToEndTester $I)
+	public function testAWeberImportWithShortcodes(EndToEndTester $I)
 	{
 		// Setup Plugin.
 		$I->setupKitPlugin($I);
@@ -65,6 +65,52 @@ public function testAWeberImport(EndToEndTester $I)
 		}
 	}
 
+	/**
+	 * Test that AWeber Blocks are replaced with Kit Blocks when the Tools > AWeber: Migrate Configuration is configured.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @param   EndToEndTester $I  Tester.
+	 */
+	public function testAWeberImportWithBlocks(EndToEndTester $I)
+	{
+		// Setup Plugin.
+		$I->setupKitPlugin($I);
+		$I->setupKitPluginResources($I);
+
+		// Create Aweber Forms.
+		$aweberFormIDs = $this->_createAWeberForms($I);
+
+		// Insert AWeber Blocks into Pages.
+		$pageIDs = $this->_createPagesWithAWeberBlocks($I, $aweberFormIDs);
+
+		// Navigate to the Tools screen.
+		$I->loadKitSettingsToolsScreen($I);
+
+		// Select the Kit Forms to replace the AWeber Forms.
+		foreach ($aweberFormIDs as $aweberFormID) {
+			$I->selectOption('_wp_convertkit_integration_aweber_settings[' . $aweberFormID . ']', $_ENV['CONVERTKIT_API_FORM_ID']);
+		}
+
+		// Click the Migrate button.
+		$I->click('Migrate');
+
+		// Confirm success message displays.
+		$I->waitForElementVisible('.notice-success');
+		$I->see('AWeber forms migrated successfully.');
+
+		// Test each Page.
+		foreach ($pageIDs as $pageID) {
+			$I->amOnPage('?p=' . $pageID);
+
+			// Check Kit Form block is displayed.
+			$I->seeElementInDOM('form[data-sv-form]');
+
+			// Confirm special characters have not been stripped.
+			$I->seeInSource('!@£$%^&amp;*()_+~!@£$%^&amp;*()_+\\');
+		}
+	}
+
 	/**
 	 * Test that the AWeber: Migrate Configuration section is not displayed when no AWeber Forms exist.
 	 *
@@ -167,6 +213,44 @@ private function _createPagesWithAWeberFormShortcodes(EndToEndTester $I, $aweber
 					'post_status'  => 'publish',
 					'post_title'   => 'Page with AWeber Form #' . $aweberFormID,
 					'post_content' => '[aweber formid="' . $aweberFormID . '"]',
+
+					// Configure Kit Plugin to not display a default Form, so we test against the Kit Form in the content.
+					'meta_input'   => [
+						'_wp_convertkit_post_meta' => [
+							'form'         => '0',
+							'landing_page' => '',
+							'tag'          => '',
+						],
+					],
+				]
+			);
+		}
+
+		return $pageIDs;
+	}
+
+	/**
+	 * Create Pages with AWeber Blocks.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @param   EndToEndTester $I  Tester.
+	 * @param   array          $aweberFormIDs  AWeber Form IDs.
+	 * @return  array
+	 */
+	private function _createPagesWithAWeberBlocks(EndToEndTester $I, $aweberFormIDs)
+	{
+		$pageIDs = array();
+
+		foreach ($aweberFormIDs as $aweberFormID) {
+			$pageIDs[] = $I->havePostInDatabase(
+				[
+					'post_type'    => 'page',
+					'post_status'  => 'publish',
+					'post_title'   => 'Page with AWeber Block #' . $aweberFormID,
+					'post_content' => '<!-- wp:aweber-signupform-block/aweber-shortcode {"selectedShortCode":"6924484-' . $aweberFormID . '-webform"} -->
+<div class="wp-block-aweber-signupform-block-aweber-shortcode">[aweber listid=6924484 formid=' . $aweberFormID . ' formtype=webform]</div>
+<!-- /wp:aweber-signupform-block/aweber-shortcode --><!-- wp:html --><div class="wp-block-core-html">Some content with characters !@£$%^&amp;*()_+~!@£$%^&amp;*()_+\\\</div><!-- /wp:html -->',
 					'meta_input'   => [
 						'_wp_convertkit_post_meta' => [
 							'form'         => '0',
diff --git a/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterMC4WPCest.php b/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterMC4WPCest.php
index 569fd0049..580ac359f 100644
--- a/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterMC4WPCest.php
+++ b/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterMC4WPCest.php
@@ -27,13 +27,13 @@ public function _before(EndToEndTester $I)
 	}
 
 	/**
-	 * Test that Mailchimp Forms are replaced with Kit Forms when the Tools > MC4WP: Migrate Configuration is configured.
+	 * Test that Mailchimp Form Shortcodes are replaced with Kit Form Shortcodes when the Tools > MC4WP: Migrate Configuration is configured.
 	 *
 	 * @since   3.1.0
 	 *
 	 * @param   EndToEndTester $I  Tester.
 	 */
-	public function testMC4WPImport(EndToEndTester $I)
+	public function testMC4WPImportWithShortcodes(EndToEndTester $I)
 	{
 		// Setup Plugin.
 		$I->setupKitPlugin($I);
@@ -67,6 +67,52 @@ public function testMC4WPImport(EndToEndTester $I)
 		}
 	}
 
+	/**
+	 * Test that Mailchimp Blocks are replaced with Kit Blocks when the Tools > MC4WP: Migrate Configuration is configured.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @param   EndToEndTester $I  Tester.
+	 */
+	public function testMC4WPImportWithBlocks(EndToEndTester $I)
+	{
+		// Setup Plugin.
+		$I->setupKitPlugin($I);
+		$I->setupKitPluginResources($I);
+
+		// Create Mailchimp Forms.
+		$mailchimpFormIDs = $this->_createMailchimpForms($I);
+
+		// Insert Mailchimp Blocks into Pages.
+		$pageIDs = $this->_createPagesWithMC4WPBlocks($I, $mailchimpFormIDs);
+
+		// Navigate to the Tools screen.
+		$I->loadKitSettingsToolsScreen($I);
+
+		// Select the Kit Forms to replace the Mailchimp Forms.
+		foreach ($mailchimpFormIDs as $mailchimpFormID) {
+			$I->selectOption('_wp_convertkit_integration_mc4wp_settings[' . $mailchimpFormID . ']', $_ENV['CONVERTKIT_API_FORM_ID']);
+		}
+
+		// Click the Migrate button.
+		$I->click('Migrate');
+
+		// Confirm success message displays.
+		$I->waitForElementVisible('.notice-success');
+		$I->see('MC4WP forms migrated successfully.');
+
+		// Test each Page.
+		foreach ($pageIDs as $pageID) {
+			$I->amOnPage('?p=' . $pageID);
+
+			// Check Kit Form block is displayed.
+			$I->seeElementInDOM('form[data-sv-form]');
+
+			// Confirm special characters have not been stripped.
+			$I->seeInSource('!@£$%^&amp;*()_+~!@£$%^&amp;*()_+\\');
+		}
+	}
+
 	/**
 	 * Test that the MC4WP: Migrate Configuration section is not displayed when no Mailchimp Forms exist.
 	 *
@@ -197,6 +243,42 @@ private function _createPagesWithMailchimpFormShortcodes(EndToEndTester $I, $mai
 		return $pageIDs;
 	}
 
+	/**
+	 * Create Pages with MC4WP Blocks.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @param   EndToEndTester $I  Tester.
+	 * @param   array          $mc4wpFormIDs  MC4WP Form IDs.
+	 * @return  array
+	 */
+	private function _createPagesWithMC4WPBlocks(EndToEndTester $I, $mc4wpFormIDs)
+	{
+		$pageIDs = array();
+
+		foreach ($mc4wpFormIDs as $mc4wpFormID) {
+			$pageIDs[] = $I->havePostInDatabase(
+				[
+					'post_type'    => 'page',
+					'post_status'  => 'publish',
+					'post_title'   => 'Page with MC4WP Block #' . $mc4wpFormID,
+					'post_content' => '<!-- wp:mailchimp-for-wp/form {"id":' . $mc4wpFormID . '} /--><!-- wp:html --><div class="wp-block-core-html">Some content with characters !@£$%^&amp;*()_+~!@£$%^&amp;*()_+\\\</div><!-- /wp:html -->',
+
+					// Configure Kit Plugin to not display a default Form, so we test against the Kit Form in the content.
+					'meta_input'   => [
+						'_wp_convertkit_post_meta' => [
+							'form'         => '0',
+							'landing_page' => '',
+							'tag'          => '',
+						],
+					],
+				]
+			);
+		}
+
+		return $pageIDs;
+	}
+
 	/**
 	 * Deactivate and reset Plugin(s) after each test, if the test passes.
 	 * We don't use _after, as this would provide a screenshot of the Plugin
diff --git a/tests/Integration/ImporterTest.php b/tests/Integration/ImporterTest.php
index 1fbbe2ca7..886c2a761 100644
--- a/tests/Integration/ImporterTest.php
+++ b/tests/Integration/ImporterTest.php
@@ -18,6 +18,15 @@ class ImporterTest extends WPTestCase
 	 */
 	protected $tester;
 
+	/**
+	 * Holds the HTML block to test, which includes special characters.
+	 *
+	 * @since   3.1.6
+	 *
+	 * @var     string
+	 */
+	private $html_block = '<!-- wp:html --><div class="wp-block-core-html">Some content with characters !@£$%^&amp;*()_+~!@£$%^&amp;*()_+\</div><!-- /wp:html -->';
+
 	/**
 	 * Performs actions before each test.
 	 *
@@ -153,6 +162,72 @@ public function testAWeberReplaceShortcodesInContentIgnoringOtherShortcodes()
 		}
 	}
 
+	/**
+	 * Test that the replace_blocks_in_post() method replaces the third party form block with the Kit form block,
+	 * and special characters are not stripped when the Post is saved.
+	 *
+	 * @since   3.1.6
+	 */
+	public function testAWeberReplaceBlocksInPost()
+	{
+		// Initialize the class we want to test.
+		$this->importer = new \ConvertKit_Admin_Importer_AWeber();
+
+		// Confirm initialization didn't result in an error.
+		$this->assertNotInstanceOf(\WP_Error::class, $this->importer);
+
+		// Create a Post with an AWeber form block and HTML block, as if the user already created this post.
+		$postID = $this->factory->post->create(
+			[
+				'post_type'    => 'page',
+				'post_status'  => 'publish',
+				'post_title'   => 'AWeber: Replace Blocks in Post',
+				'post_content' => str_replace(
+					'\\',
+					'\\\\',
+					'<!-- wp:aweber-signupform-block/aweber-shortcode {"selectedShortCode":"6924484-289586845-webform"} -->
+<div class="wp-block-aweber-signupform-block-aweber-shortcode">[aweber listid=6924484 formid=289586845 formtype=webform]</div>
+<!-- /wp:aweber-signupform-block/aweber-shortcode -->' . $this->html_block
+				),
+			]
+		);
+
+		// Replace the blocks in the post.
+		$this->importer->replace_blocks_in_post( $postID, 289586845, $_ENV['CONVERTKIT_API_FORM_ID'] );
+
+		// Test the block is replaced with the Kit form block, and special characters are not stripped.
+		$this->assertEquals(
+			'<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"} /-->' . $this->html_block,
+			get_post_field( 'post_content', $postID )
+		);
+	}
+
+	/**
+	 * Test that the replace_blocks_in_content() method replaces the third party form block with the Kit form block,
+	 * and special characters are not stripped.
+	 *
+	 * @since   3.1.6
+	 */
+	public function testAWeberReplaceBlocksInContent()
+	{
+		// Initialize the class we want to test.
+		$this->importer = new \ConvertKit_Admin_Importer_AWeber();
+
+		// Confirm initialization didn't result in an error.
+		$this->assertNotInstanceOf(\WP_Error::class, $this->importer);
+
+		// Define the blocks to test.
+		$content = '<!-- wp:aweber-signupform-block/aweber-shortcode {"selectedShortCode":"6924484-289586845-webform"} -->
+<div class="wp-block-aweber-signupform-block-aweber-shortcode">[aweber listid=6924484 formid=289586845 formtype=webform]</div>
+<!-- /wp:aweber-signupform-block/aweber-shortcode -->' . $this->html_block;
+
+		// Test the block is replaced with the Kit form block.
+		$this->assertEquals(
+			'<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"} /-->' . $this->html_block,
+			$this->importer->replace_blocks_in_content( parse_blocks( $content ), 289586845, $_ENV['CONVERTKIT_API_FORM_ID'] )
+		);
+	}
+
 	/**
 	 * Test that the get_form_ids_from_content() method returns MC4WP form shortcode Form IDs
 	 * ignoring any other shortcodes.
@@ -256,4 +331,62 @@ public function testMC4WPReplaceShortcodesInContentIgnoringOtherShortcodes()
 			);
 		}
 	}
+
+	/**
+	 * Test that the replace_blocks_in_post() method replaces the third party form block with the Kit form block,
+	 * and special characters are not stripped when the Post is saved.
+	 *
+	 * @since   3.1.6
+	 */
+	public function testMC4WPReplaceBlocksInPost()
+	{
+		// Initialize the class we want to test.
+		$this->importer = new \ConvertKit_Admin_Importer_MC4WP();
+
+		// Confirm initialization didn't result in an error.
+		$this->assertNotInstanceOf(\WP_Error::class, $this->importer);
+
+		// Create a Post with a MC4WP form block and HTML block, as if the user already created this post.
+		$postID = $this->factory->post->create(
+			[
+				'post_type'    => 'page',
+				'post_status'  => 'publish',
+				'post_title'   => 'Mailchimp 4 WP: Replace Blocks in Post',
+				'post_content' => str_replace( '\\', '\\\\', '<!-- wp:mailchimp-for-wp/form {"id":4410} /-->' . $this->html_block ),
+			]
+		);
+
+		// Replace the blocks in the post.
+		$this->importer->replace_blocks_in_post( $postID, 4410, $_ENV['CONVERTKIT_API_FORM_ID'] );
+
+		// Test the block is replaced with the Kit form block, and special characters are not stripped.
+		$this->assertEquals(
+			'<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"} /-->' . $this->html_block,
+			get_post_field( 'post_content', $postID )
+		);
+	}
+
+	/**
+	 * Test that the replace_blocks_in_content() method replaces the third party form block with the Kit form block,
+	 * and special characters are not stripped.
+	 *
+	 * @since   3.1.6
+	 */
+	public function testMC4WPReplaceBlocksInContent()
+	{
+		// Initialize the class we want to test.
+		$this->importer = new \ConvertKit_Admin_Importer_MC4WP();
+
+		// Confirm initialization didn't result in an error.
+		$this->assertNotInstanceOf(\WP_Error::class, $this->importer);
+
+		// Define the blocks to test.
+		$content = '<!-- wp:mailchimp-for-wp/form {"id":4410} /-->' . $this->html_block;
+
+		// Test the block is replaced with the Kit form block.
+		$this->assertEquals(
+			'<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"} /-->' . $this->html_block,
+			$this->importer->replace_blocks_in_content( parse_blocks( $content ), 4410, $_ENV['CONVERTKIT_API_FORM_ID'] )
+		);
+	}
 }