From 78dfd76cf385760cce78929a24cb51de00734635 Mon Sep 17 00:00:00 2001
From: Tim Carr <tim@n7studios.co.uk>
Date: Mon, 19 Jan 2026 16:07:53 +0800
Subject: [PATCH 1/7] Importer: Convert Third Party Form Blocks to Kit Form
 Block

---
 ...class-convertkit-admin-importer-aweber.php |  18 ++
 .../class-convertkit-admin-importer-mc4wp.php |  18 ++
 .../class-convertkit-admin-importer.php       | 285 ++++++++++++++----
 .../class-convertkit-admin-section-tools.php  |   2 +
 4 files changed, 258 insertions(+), 65 deletions(-)

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..8bfff6d68 100644
--- a/admin/importers/class-convertkit-admin-importer.php
+++ b/admin/importers/class-convertkit-admin-importer.php
@@ -32,6 +32,15 @@ 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 = '';
+
 	/**
 	 * Returns an array of third party form IDs and titles.
 	 *
@@ -42,7 +51,7 @@ 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 shortcode or block.
 	 *
 	 * @since   3.1.5
 	 *
@@ -52,17 +61,21 @@ 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 shortcode or block 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 . '%'
 			)
 		);
 
@@ -97,30 +110,107 @@ public function has_forms_in_posts() {
 	}
 
 	/**
-	 * Replaces the third party form shortcode with the Kit form shortcode.
+	 * Returns an array of all unique form IDs from the posts that contain the third party form shortcode.
 	 *
-	 * @since   3.1.0
+	 * @since   3.1.5
+	 *
+	 * @return  array
+	 */
+	public function get_form_ids_in_posts() {
+
+		// Get Post IDs that contain the third party form shortcode.
+		$post_ids = $this->get_forms_in_posts();
+
+		// If no post IDs are found, return an empty array.
+		if ( ! count( $post_ids ) ) {
+			return array();
+		}
+
+		// Iterate through Posts, extracting the Form IDs from the third party form shortcodes.
+		$form_ids = array();
+		foreach ( $post_ids as $post_id ) {
+			$content_form_ids = $this->get_form_ids_from_content( get_post_field( 'post_content', $post_id ) );
+			$form_ids         = array_merge( $form_ids, $content_form_ids );
+		}
+
+		$form_ids = array_values( array_unique( $form_ids ) );
+
+		return $form_ids;
+
+	}
+
+	/**
+	 * Returns an array of form IDs within the third party form shortcode or block.
+	 *
+	 * @since   3.1.5
+	 *
+	 * @param   string $content             Content containing third party form shortcode or block.
+	 * @return  array
+	 */
+	public function get_form_ids_from_content( $content ) {
+
+		// Shortcodes.
+		$pattern = '/\['                                       // Start regex with an opening square bracket.
+			. preg_quote( $this->shortcode_name, '/' )         // Match the shortcode name, escaping any regex special chars.
+			. '(?:\s+[^\]]*)?'                                 // Optionally match any attributes (key/value pairs), non-greedy.
+			. preg_quote( $this->shortcode_id_attribute, '/' ) // Match the id attribute name.
+			. '\s*=\s*'                                        // Optional whitespace, equals sign, optional whitespace.
+			. '(?:"([^"]+)"|([^\s\]]+))'                       // Capture quoted or unquoted value.
+			. '[^\]]*?\]/i';                                   // Match up to closing bracket, case-insensitive.
+
+		preg_match_all( $pattern, $content, $matches );
+
+		// Extract form IDs: They could be in either $matches[1] (quoted) or $matches[2] (unquoted).
+		$form_ids = array_filter(
+			array_merge(
+				isset( $matches[1] ) ? $matches[1] : array(),
+				isset( $matches[2] ) ? $matches[2] : array()
+			)
+		);
+
+		// Blocks.
+		// @TODO.
+
+		return $form_ids;
+
+	}
+
+	/**
+	 * Replaces the third party form block with the Kit form block.
+	 *
+	 * @since   3.1.6
 	 *
 	 * @param   int $third_party_form_id    The ID of the third party form.
 	 * @param   int $form_id                The ID of the Kit form.
 	 */
-	public function replace_shortcodes_in_posts( $third_party_form_id, $form_id ) {
+	public function replace_blocks_in_posts( $third_party_form_id, $form_id ) {
 
-		// Get Posts that contain the third party Form Shortcode.
+		// Get Posts that contain the third party Form Block.
 		$posts = $this->get_forms_in_posts();
 
-		// Bail if no Posts contain the third party Form Shortcode.
+		// Bail if no Posts contain the third party Form Block.
 		if ( empty( $posts ) ) {
 			return;
 		}
 
-		// Iterate through Posts and replace the third party Form Shortcode with the Kit Form Shortcode.
+		// Iterate through Posts and replace the third party Form Block with the Kit Form Block.
 		foreach ( $posts as $post_id ) {
 			// Get Post content.
 			$post_content = get_post_field( 'post_content', $post_id );
 
-			// Replace the third party Form Shortcode with the Kit Form Shortcode.
-			$post_content = $this->replace_shortcodes_in_content( $post_content, $third_party_form_id, $form_id );
+			// Fetch Blocks from Content.
+			$blocks = parse_blocks( $post_content );
+
+			// Bail if no Blocks exist (i.e. we're not using Gutenberg).
+			if ( ! is_array( $blocks ) ) {
+				continue;
+			}
+			if ( ! count( $blocks ) ) {
+				continue;
+			}
+
+			// Replace the third party Form Block with the Kit Form Block.
+			$post_content = $this->replace_blocks_in_content( $post_content, $third_party_form_id, $form_id );
 
 			// Update the Post content.
 			wp_update_post(
@@ -137,94 +227,159 @@ public function replace_shortcodes_in_posts( $third_party_form_id, $form_id ) {
 	}
 
 	/**
-	 * Replaces the third party form shortcode with the Kit form shortcode in the given string.
+	 * Replaces the third party form block with the Kit form block in the given string.
 	 *
-	 * @since   3.1.0
+	 * @since   3.1.6
 	 *
-	 * @param   string $content             Content containing third party Form Shortcodes.
+	 * @param   string $content                Content containing third party Form Blocks.
 	 * @param   int    $third_party_form_id    Third Party Form ID.
 	 * @param   int    $form_id                Kit Form ID.
 
 	 * @return  string
 	 */
-	public function replace_shortcodes_in_content( $content, $third_party_form_id, $form_id ) {
+	public function replace_blocks_in_content( $content, $third_party_form_id, $form_id ) {
 
-		$pattern = '/\['                                     // Start regex with an opening square bracket.
-			. preg_quote( $this->shortcode_name, '/' )       // Match the shortcode name, escaping any regex special chars.
-			. '[^\]]*?'                                      // Match any characters that are not a closing square bracket, non-greedy.
-			. '\b' . preg_quote( $this->shortcode_id_attribute, '/' ) // Match the id attribute word boundary and escape as needed.
-			. '\s*=\s*'                                      // Match optional whitespace around an equals sign.
-			. '(?:"' . preg_quote( (string) $third_party_form_id, '/' ) . '"|' . preg_quote( (string) $third_party_form_id, '/' ) . ')' // Match the form ID, quoted or unquoted.
-			. '[^\]]*?\]/i';                                 // Match any other characters (non-greedy) up to the closing square bracket, case-insensitive.
+		// Fetch Blocks from Content.
+		$blocks = parse_blocks( $content );
 
-		return preg_replace(
-			$pattern,
-			'[convertkit_form id="' . $form_id . '"]',
-			$content
-		);
+		// Bail if no Blocks exist (i.e. we're not using Gutenberg).
+		if ( ! is_array( $blocks ) ) {
+			return $content;
+		}
+		if ( ! count( $blocks ) ) {
+			return $content;
+		}
+
+		// Recursively convert blocks.
+		$blocks = $this->recursively_convert_blocks( $blocks, $third_party_form_id, $form_id );
+
+		// Serialize blocks.
+		return serialize_blocks( $blocks );
 
 	}
 
 	/**
-	 * Returns an array of all unique form IDs from the posts that contain the third party form shortcode.
+	 * Recursively walks through an array of blocks and innerBlocks,
+	 * converting third party form blocks to Kit form blocks.
 	 *
-	 * @since   3.1.5
+	 * @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
 	 */
-	public function get_form_ids_in_posts() {
+	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 ], $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(),
+			);
+		}
 
-		// Get Post IDs that contain the third party form shortcode.
-		$post_ids = $this->get_forms_in_posts();
+		return $blocks;
 
-		// If no post IDs are found, return an empty array.
-		if ( ! count( $post_ids ) ) {
-			return array();
-		}
+	}
 
-		// Iterate through Posts, extracting the Form IDs from the third party form shortcodes.
-		$form_ids = array();
-		foreach ( $post_ids as $post_id ) {
-			$content_form_ids = $this->get_form_ids_from_content( get_post_field( 'post_content', $post_id ) );
-			$form_ids         = array_merge( $form_ids, $content_form_ids );
+	/**
+	 * Replaces the third party form shortcode with the Kit form shortcode.
+	 *
+	 * @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.
+	 */
+	public function replace_shortcodes_in_posts( $third_party_form_id, $form_id ) {
+
+		// Get Posts that contain the third party Form Shortcode.
+		$posts = $this->get_forms_in_posts();
+
+		// Bail if no Posts contain the third party Form Shortcode.
+		if ( empty( $posts ) ) {
+			return;
 		}
 
-		$form_ids = array_values( array_unique( $form_ids ) );
+		// Iterate through Posts and replace the third party Form Shortcode with the Kit Form Shortcode.
+		foreach ( $posts as $post_id ) {
+			// Get Post content.
+			$post_content = get_post_field( 'post_content', $post_id );
 
-		return $form_ids;
+			// Replace the third party Form Shortcode with the Kit Form Shortcode.
+			$post_content = $this->replace_shortcodes_in_content( $post_content, $third_party_form_id, $form_id );
+
+			// Update the Post content.
+			wp_update_post(
+				array(
+					'ID'           => $post_id,
+					'post_content' => $post_content,
+				),
+				false,
+				false // Don't fire after action hooks.
+			);
+
+		}
 
 	}
 
 	/**
-	 * Returns an array of form IDs within the shortcode for the third party Form plugin.
+	 * Replaces the third party form shortcode with the Kit form shortcode in the given string.
 	 *
-	 * @since   3.1.5
+	 * @since   3.1.0
 	 *
 	 * @param   string $content             Content containing third party Form Shortcodes.
-	 * @return  array
-	 */
-	public function get_form_ids_from_content( $content ) {
+	 * @param   int    $third_party_form_id    Third Party Form ID.
+	 * @param   int    $form_id                Kit Form ID.
 
-		$pattern = '/\['                                       // Start regex with an opening square bracket.
-			. preg_quote( $this->shortcode_name, '/' )         // Match the shortcode name, escaping any regex special chars.
-			. '(?:\s+[^\]]*)?'                                 // Optionally match any attributes (key/value pairs), non-greedy.
-			. preg_quote( $this->shortcode_id_attribute, '/' ) // Match the id attribute name.
-			. '\s*=\s*'                                        // Optional whitespace, equals sign, optional whitespace.
-			. '(?:"([^"]+)"|([^\s\]]+))'                       // Capture quoted or unquoted value.
-			. '[^\]]*?\]/i';                                   // Match up to closing bracket, case-insensitive.
+	 * @return  string
+	 */
+	public function replace_shortcodes_in_content( $content, $third_party_form_id, $form_id ) {
 
-		preg_match_all( $pattern, $content, $matches );
+		$pattern = '/\['                                     // Start regex with an opening square bracket.
+			. preg_quote( $this->shortcode_name, '/' )       // Match the shortcode name, escaping any regex special chars.
+			. '[^\]]*?'                                      // Match any characters that are not a closing square bracket, non-greedy.
+			. '\b' . preg_quote( $this->shortcode_id_attribute, '/' ) // Match the id attribute word boundary and escape as needed.
+			. '\s*=\s*'                                      // Match optional whitespace around an equals sign.
+			. '(?:"' . preg_quote( (string) $third_party_form_id, '/' ) . '"|' . preg_quote( (string) $third_party_form_id, '/' ) . ')' // Match the form ID, quoted or unquoted.
+			. '[^\]]*?\]/i';                                 // Match any other characters (non-greedy) up to the closing square bracket, case-insensitive.
 
-		// Extract form IDs: They could be in either $matches[1] (quoted) or $matches[2] (unquoted).
-		$form_ids = array_filter(
-			array_merge(
-				isset( $matches[1] ) ? $matches[1] : array(),
-				isset( $matches[2] ) ? $matches[2] : array()
-			)
+		return preg_replace(
+			$pattern,
+			'[convertkit_form id="' . $form_id . '"]',
+			$content
 		);
 
-		return $form_ids;
-
 	}
 
 }
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 );
 		}
 

From 4ea734fa7e8aad967b072eeace96d8824d2b6a20 Mon Sep 17 00:00:00 2001
From: Tim Carr <tim@n7studios.co.uk>
Date: Mon, 19 Jan 2026 16:24:36 +0800
Subject: [PATCH 2/7] =?UTF-8?q?Don=E2=80=99t=20fetch=20form=20IDs=20from?=
 =?UTF-8?q?=20blocks?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 admin/importers/class-convertkit-admin-importer.php | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/admin/importers/class-convertkit-admin-importer.php b/admin/importers/class-convertkit-admin-importer.php
index 8bfff6d68..34cb3d806 100644
--- a/admin/importers/class-convertkit-admin-importer.php
+++ b/admin/importers/class-convertkit-admin-importer.php
@@ -140,16 +140,15 @@ public function get_form_ids_in_posts() {
 	}
 
 	/**
-	 * Returns an array of form IDs within the third party form shortcode or block.
+	 * Returns an array of form IDs within the third party form shortcode.
 	 *
 	 * @since   3.1.5
 	 *
-	 * @param   string $content             Content containing third party form shortcode or block.
+	 * @param   string $content             Content containing third party form shortcode.
 	 * @return  array
 	 */
 	public function get_form_ids_from_content( $content ) {
 
-		// Shortcodes.
 		$pattern = '/\['                                       // Start regex with an opening square bracket.
 			. preg_quote( $this->shortcode_name, '/' )         // Match the shortcode name, escaping any regex special chars.
 			. '(?:\s+[^\]]*)?'                                 // Optionally match any attributes (key/value pairs), non-greedy.
@@ -168,9 +167,6 @@ public function get_form_ids_from_content( $content ) {
 			)
 		);
 
-		// Blocks.
-		// @TODO.
-
 		return $form_ids;
 
 	}

From 008687a55ece1b532ed983d5f406e6c45e5baf70 Mon Sep 17 00:00:00 2001
From: Tim Carr <tim@n7studios.co.uk>
Date: Mon, 19 Jan 2026 16:29:15 +0800
Subject: [PATCH 3/7] Move new functions to end of class

---
 .../class-convertkit-admin-importer.php       | 155 +++++++++---------
 1 file changed, 82 insertions(+), 73 deletions(-)

diff --git a/admin/importers/class-convertkit-admin-importer.php b/admin/importers/class-convertkit-admin-importer.php
index 34cb3d806..3858fc869 100644
--- a/admin/importers/class-convertkit-admin-importer.php
+++ b/admin/importers/class-convertkit-admin-importer.php
@@ -41,6 +41,15 @@ abstract class ConvertKit_Admin_Importer {
 	 */
 	public $block_name = '';
 
+	/**
+	 * Holds the 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.
 	 *
@@ -51,7 +60,7 @@ abstract class ConvertKit_Admin_Importer {
 	abstract public function get_forms();
 
 	/**
-	 * Returns an array of post IDs that contain the third party form shortcode or block.
+	 * Returns an array of post IDs that contain the third partyform shortcode.
 	 *
 	 * @since   3.1.5
 	 *
@@ -61,7 +70,7 @@ public function get_forms_in_posts() {
 
 		global $wpdb;
 
-		// Search post_content for the third party form shortcode or block and return array of post IDs.
+		// Search post_content for the third party form shortcode and return array of post IDs.
 		$results = $wpdb->get_col(
 			$wpdb->prepare(
 				"
@@ -109,6 +118,75 @@ public function has_forms_in_posts() {
 
 	}
 
+	/**
+	 * Replaces the third party form shortcode with the Kit form shortcode.
+	 *
+	 * @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.
+	 */
+	public function replace_shortcodes_in_posts( $third_party_form_id, $form_id ) {
+
+		// Get Posts that contain the third party Form Shortcode.
+		$posts = $this->get_forms_in_posts();
+
+		// Bail if no Posts contain the third party Form Shortcode.
+		if ( empty( $posts ) ) {
+			return;
+		}
+
+		// Iterate through Posts and replace the third party Form Shortcode with the Kit Form Shortcode.
+		foreach ( $posts as $post_id ) {
+			// Get Post content.
+			$post_content = get_post_field( 'post_content', $post_id );
+
+			// Replace the third party Form Shortcode with the Kit Form Shortcode.
+			$post_content = $this->replace_shortcodes_in_content( $post_content, $third_party_form_id, $form_id );
+
+			// 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 shortcode with the Kit form shortcode in the given string.
+	 *
+	 * @since   3.1.0
+	 *
+	 * @param   string $content             Content containing third party Form Shortcodes.
+	 * @param   int    $third_party_form_id    Third Party Form ID.
+	 * @param   int    $form_id                Kit Form ID.
+
+	 * @return  string
+	 */
+	public function replace_shortcodes_in_content( $content, $third_party_form_id, $form_id ) {
+
+		$pattern = '/\['                                     // Start regex with an opening square bracket.
+			. preg_quote( $this->shortcode_name, '/' )       // Match the shortcode name, escaping any regex special chars.
+			. '[^\]]*?'                                      // Match any characters that are not a closing square bracket, non-greedy.
+			. '\b' . preg_quote( $this->shortcode_id_attribute, '/' ) // Match the id attribute word boundary and escape as needed.
+			. '\s*=\s*'                                      // Match optional whitespace around an equals sign.
+			. '(?:"' . preg_quote( (string) $third_party_form_id, '/' ) . '"|' . preg_quote( (string) $third_party_form_id, '/' ) . ')' // Match the form ID, quoted or unquoted.
+			. '[^\]]*?\]/i';                                 // Match any other characters (non-greedy) up to the closing square bracket, case-insensitive.
+
+		return preg_replace(
+			$pattern,
+			'[convertkit_form id="' . $form_id . '"]',
+			$content
+		);
+
+	}
+
 	/**
 	 * Returns an array of all unique form IDs from the posts that contain the third party form shortcode.
 	 *
@@ -140,11 +218,11 @@ public function get_form_ids_in_posts() {
 	}
 
 	/**
-	 * Returns an array of form IDs within the third party form shortcode.
+	 * Returns an array of form IDs within the shortcode for the third party Form plugin.
 	 *
 	 * @since   3.1.5
 	 *
-	 * @param   string $content             Content containing third party form shortcode.
+	 * @param   string $content             Content containing third party Form Shortcodes.
 	 * @return  array
 	 */
 	public function get_form_ids_from_content( $content ) {
@@ -309,73 +387,4 @@ private function recursively_convert_blocks( $blocks, $third_party_form_id, $for
 
 	}
 
-	/**
-	 * Replaces the third party form shortcode with the Kit form shortcode.
-	 *
-	 * @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.
-	 */
-	public function replace_shortcodes_in_posts( $third_party_form_id, $form_id ) {
-
-		// Get Posts that contain the third party Form Shortcode.
-		$posts = $this->get_forms_in_posts();
-
-		// Bail if no Posts contain the third party Form Shortcode.
-		if ( empty( $posts ) ) {
-			return;
-		}
-
-		// Iterate through Posts and replace the third party Form Shortcode with the Kit Form Shortcode.
-		foreach ( $posts as $post_id ) {
-			// Get Post content.
-			$post_content = get_post_field( 'post_content', $post_id );
-
-			// Replace the third party Form Shortcode with the Kit Form Shortcode.
-			$post_content = $this->replace_shortcodes_in_content( $post_content, $third_party_form_id, $form_id );
-
-			// 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 shortcode with the Kit form shortcode in the given string.
-	 *
-	 * @since   3.1.0
-	 *
-	 * @param   string $content             Content containing third party Form Shortcodes.
-	 * @param   int    $third_party_form_id    Third Party Form ID.
-	 * @param   int    $form_id                Kit Form ID.
-
-	 * @return  string
-	 */
-	public function replace_shortcodes_in_content( $content, $third_party_form_id, $form_id ) {
-
-		$pattern = '/\['                                     // Start regex with an opening square bracket.
-			. preg_quote( $this->shortcode_name, '/' )       // Match the shortcode name, escaping any regex special chars.
-			. '[^\]]*?'                                      // Match any characters that are not a closing square bracket, non-greedy.
-			. '\b' . preg_quote( $this->shortcode_id_attribute, '/' ) // Match the id attribute word boundary and escape as needed.
-			. '\s*=\s*'                                      // Match optional whitespace around an equals sign.
-			. '(?:"' . preg_quote( (string) $third_party_form_id, '/' ) . '"|' . preg_quote( (string) $third_party_form_id, '/' ) . ')' // Match the form ID, quoted or unquoted.
-			. '[^\]]*?\]/i';                                 // Match any other characters (non-greedy) up to the closing square bracket, case-insensitive.
-
-		return preg_replace(
-			$pattern,
-			'[convertkit_form id="' . $form_id . '"]',
-			$content
-		);
-
-	}
-
 }

From e3a0eeb8954f4fa3e39df8dbd5dd26c840e15d3f Mon Sep 17 00:00:00 2001
From: Tim Carr <tim@n7studios.co.uk>
Date: Mon, 19 Jan 2026 16:39:50 +0800
Subject: [PATCH 4/7] Added Integration Tests

---
 tests/Integration/ImporterTest.php | 98 ++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)

diff --git a/tests/Integration/ImporterTest.php b/tests/Integration/ImporterTest.php
index 1fbbe2ca7..6ce2175ee 100644
--- a/tests/Integration/ImporterTest.php
+++ b/tests/Integration/ImporterTest.php
@@ -153,6 +153,57 @@ public function testAWeberReplaceShortcodesInContentIgnoringOtherShortcodes()
 		}
 	}
 
+	/**
+	 * Test that the replace_blocks_in_content() method replaces the third party form block with the Kit form block.
+	 *
+	 * @since   3.1.5
+	 */
+	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 -->';
+
+		// Test the block is replaced with the Kit form block.
+		$this->assertEquals(
+			'<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"} /-->',
+			$this->importer->replace_blocks_in_content( $content, 289586845, $_ENV['CONVERTKIT_API_FORM_ID'] )
+		);
+	}
+
+	/**
+	 * Test that the replace_blocks_in_content() method ignores non-AWeber blocks.
+	 *
+	 * @since   3.1.5
+	 */
+	public function testAWeberReplaceBlocksInContentIgnoringOtherBlocks()
+	{
+		// 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.
+		$html_block = '<!-- wp:html --><div class="wp-block-core-html">Some content</div><!-- /wp:html -->';
+		$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 -->' . $html_block;
+
+		// Test the block is replaced with the Kit form block.
+		$this->assertEquals(
+			'<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"} /-->' . $html_block,
+			$this->importer->replace_blocks_in_content( $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 +307,51 @@ public function testMC4WPReplaceShortcodesInContentIgnoringOtherShortcodes()
 			);
 		}
 	}
+
+	/**
+	 * Test that the replace_blocks_in_content() method replaces the third party form block with the Kit form block.
+	 *
+	 * @since   3.1.5
+	 */
+	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} /-->';
+
+		// Test the block is replaced with the Kit form block.
+		$this->assertEquals(
+			'<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"} /-->',
+			$this->importer->replace_blocks_in_content( $content, 4410, $_ENV['CONVERTKIT_API_FORM_ID'] )
+		);
+	}
+
+	/**
+	 * Test that the replace_blocks_in_content() method ignores non-MC4WP blocks.
+	 *
+	 * @since   3.1.5
+	 */
+	public function testMC4WPReplaceBlocksInContentIgnoringOtherBlocks()
+	{
+		// 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.
+		$html_block = '<!-- wp:html --><div class="wp-block-core-html">Some content</div><!-- /wp:html -->';
+		$content    = '<!-- wp:mailchimp-for-wp/form {"id":4410} /-->' . $html_block;
+
+		// Test the block is replaced with the Kit form block.
+		$this->assertEquals(
+			'<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"} /-->' . $html_block,
+			$this->importer->replace_blocks_in_content( $content, 4410, $_ENV['CONVERTKIT_API_FORM_ID'] )
+		);
+	}
 }

From 3a63e872c8714ef3ee22aa5c33e683b4797d731f Mon Sep 17 00:00:00 2001
From: Tim Carr <tim@n7studios.co.uk>
Date: Mon, 19 Jan 2026 16:45:07 +0800
Subject: [PATCH 5/7] Added End to End Tests

---
 .../PluginSettingsToolsImporterAweberCest.php | 79 ++++++++++++++++++-
 .../PluginSettingsToolsImporterMC4WPCest.php  | 72 ++++++++++++++++-
 2 files changed, 148 insertions(+), 3 deletions(-)

diff --git a/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterAweberCest.php b/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterAweberCest.php
index 27bdfca60..0df53fb63 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 +65,47 @@ public function testAWeberImport(EndToEndTester $I)
 		}
 	}
 
+	/**
+	 * Test that AWeber Blocks are replaced with Kit Blocks when the Tools > AWeber: Migrate Configuration is configured.
+	 *
+	 * @since   3.1.5
+	 *
+	 * @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');
+		$I->see('AWeber forms migrated successfully.');
+
+		// View the Pages, to confirm Kit Forms now display.
+		foreach ($pageIDs as $pageID) {
+			$I->amOnPage('?p=' . $pageID);
+			$I->seeElementInDOM('form[data-sv-form]');
+		}
+	}
+
 	/**
 	 * Test that the AWeber: Migrate Configuration section is not displayed when no AWeber Forms exist.
 	 *
@@ -181,6 +222,42 @@ private function _createPagesWithAWeberFormShortcodes(EndToEndTester $I, $aweber
 		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 -->',
+					'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/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterMC4WPCest.php b/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterMC4WPCest.php
index 569fd0049..2336c6d23 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 +67,47 @@ public function testMC4WPImport(EndToEndTester $I)
 		}
 	}
 
+	/**
+	 * Test that Mailchimp Blocks are replaced with Kit Blocks when the Tools > MC4WP: Migrate Configuration is configured.
+	 *
+	 * @since   3.1.0
+	 *
+	 * @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');
+		$I->see('MC4WP forms migrated successfully.');
+
+		// View the Pages, to confirm Kit Forms now display.
+		foreach ($pageIDs as $pageID) {
+			$I->amOnPage('?p=' . $pageID);
+			$I->seeElementInDOM('form[data-sv-form]');
+		}
+	}
+
 	/**
 	 * Test that the MC4WP: Migrate Configuration section is not displayed when no Mailchimp Forms exist.
 	 *
@@ -197,6 +238,33 @@ 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 . '} /-->',
+				]
+			);
+		}
+
+		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

From 7d7baa4373664758b90d697a5791c29c9983fd0d Mon Sep 17 00:00:00 2001
From: Tim Carr <tim@n7studios.co.uk>
Date: Mon, 19 Jan 2026 16:57:48 +0800
Subject: [PATCH 6/7] PHPStan compat.

---
 .../class-convertkit-admin-importer.php          | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/admin/importers/class-convertkit-admin-importer.php b/admin/importers/class-convertkit-admin-importer.php
index 3858fc869..50de5785d 100644
--- a/admin/importers/class-convertkit-admin-importer.php
+++ b/admin/importers/class-convertkit-admin-importer.php
@@ -275,11 +275,8 @@ public function replace_blocks_in_posts( $third_party_form_id, $form_id ) {
 			// Fetch Blocks from Content.
 			$blocks = parse_blocks( $post_content );
 
-			// Bail if no Blocks exist (i.e. we're not using Gutenberg).
-			if ( ! is_array( $blocks ) ) {
-				continue;
-			}
-			if ( ! count( $blocks ) ) {
+			// 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'] ) ) {
 				continue;
 			}
 
@@ -316,11 +313,8 @@ public function replace_blocks_in_content( $content, $third_party_form_id, $form
 		// Fetch Blocks from Content.
 		$blocks = parse_blocks( $content );
 
-		// Bail if no Blocks exist (i.e. we're not using Gutenberg).
-		if ( ! is_array( $blocks ) ) {
-			return $content;
-		}
-		if ( ! count( $blocks ) ) {
+		// 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 $content;
 		}
 
@@ -367,7 +361,7 @@ private function recursively_convert_blocks( $blocks, $third_party_form_id, $for
 			}
 
 			// 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 ], $third_party_form_id ) === false ) {
+			if ( stripos( $block['attrs'][ $this->block_id_attribute ], (string) $third_party_form_id ) === false ) {
 				continue;
 			}
 

From a6285b7b5f232a624ca79968672910654bb6893d Mon Sep 17 00:00:00 2001
From: Tim Carr <tim@n7studios.co.uk>
Date: Tue, 20 Jan 2026 15:49:19 +0800
Subject: [PATCH 7/7] Improve test coverage

---
 .../class-convertkit-admin-importer.php       | 90 +++++++++--------
 .../PluginSettingsToolsImporterAweberCest.php | 13 ++-
 .../PluginSettingsToolsImporterMC4WPCest.php  | 20 +++-
 tests/Integration/ImporterTest.php            | 99 +++++++++++++------
 4 files changed, 144 insertions(+), 78 deletions(-)

diff --git a/admin/importers/class-convertkit-admin-importer.php b/admin/importers/class-convertkit-admin-importer.php
index 50de5785d..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
 	 *
@@ -42,7 +42,7 @@ abstract class ConvertKit_Admin_Importer {
 	public $block_name = '';
 
 	/**
-	 * Holds the ID attribute name for the third party Form plugin.
+	 * Holds the block ID attribute name for the third party Form plugin.
 	 *
 	 * @since   3.1.6
 	 *
@@ -60,7 +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
 	 *
@@ -70,7 +70,7 @@ 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(
 				"
@@ -123,8 +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 ) {
 
@@ -254,8 +254,8 @@ public function get_form_ids_from_content( $content ) {
 	 *
 	 * @since   3.1.6
 	 *
-	 * @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_blocks_in_posts( $third_party_form_id, $form_id ) {
 
@@ -269,32 +269,50 @@ public function replace_blocks_in_posts( $third_party_form_id, $form_id ) {
 
 		// Iterate through Posts and replace the third party Form Block with the Kit Form Block.
 		foreach ( $posts as $post_id ) {
-			// Get Post content.
-			$post_content = get_post_field( 'post_content', $post_id );
+			$this->replace_blocks_in_post( $post_id, $third_party_form_id, $form_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'] ) ) {
-				continue;
-			}
+	/**
+	 * 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 ) {
 
-			// Replace the third party Form Block with the Kit Form Block.
-			$post_content = $this->replace_blocks_in_content( $post_content, $third_party_form_id, $form_id );
+		// Get Post content.
+		$post_content = get_post_field( 'post_content', $post_id );
 
-			// Update the Post content.
-			wp_update_post(
-				array(
-					'ID'           => $post_id,
-					'post_content' => $post_content,
-				),
-				false,
-				false // Don't fire after action hooks.
-			);
+		// 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.
+		);
+
 	}
 
 	/**
@@ -302,21 +320,13 @@ public function replace_blocks_in_posts( $third_party_form_id, $form_id ) {
 	 *
 	 * @since   3.1.6
 	 *
-	 * @param   string $content                Content containing third party Form Blocks.
-	 * @param   int    $third_party_form_id    Third Party Form ID.
-	 * @param   int    $form_id                Kit Form ID.
-
+	 * @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( $content, $third_party_form_id, $form_id ) {
-
-		// Fetch Blocks from Content.
-		$blocks = parse_blocks( $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 $content;
-		}
+	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 );
diff --git a/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterAweberCest.php b/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterAweberCest.php
index 0df53fb63..9c9046a67 100644
--- a/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterAweberCest.php
+++ b/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterAweberCest.php
@@ -68,7 +68,7 @@ public function testAWeberImportWithShortcodes(EndToEndTester $I)
 	/**
 	 * Test that AWeber Blocks are replaced with Kit Blocks when the Tools > AWeber: Migrate Configuration is configured.
 	 *
-	 * @since   3.1.5
+	 * @since   3.1.6
 	 *
 	 * @param   EndToEndTester $I  Tester.
 	 */
@@ -99,10 +99,15 @@ public function testAWeberImportWithBlocks(EndToEndTester $I)
 		$I->waitForElementVisible('.notice-success');
 		$I->see('AWeber forms migrated successfully.');
 
-		// View the Pages, to confirm Kit Forms now display.
+		// 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;*()_+\\');
 		}
 	}
 
@@ -208,6 +213,8 @@ 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',
@@ -243,7 +250,7 @@ private function _createPagesWithAWeberBlocks(EndToEndTester $I, $aweberFormIDs)
 					'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=' . $aweberFormID . ' formtype=webform]</div>
-<!-- /wp:aweber-signupform-block/aweber-shortcode -->',
+<!-- /wp:aweber-signupform-block/aweber-shortcode --><!-- wp:html --><div class="wp-block-core-html">Some content with characters !@£$%^&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 2336c6d23..580ac359f 100644
--- a/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterMC4WPCest.php
+++ b/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterMC4WPCest.php
@@ -70,7 +70,7 @@ public function testMC4WPImportWithShortcodes(EndToEndTester $I)
 	/**
 	 * Test that Mailchimp Blocks are replaced with Kit Blocks when the Tools > MC4WP: Migrate Configuration is configured.
 	 *
-	 * @since   3.1.0
+	 * @since   3.1.6
 	 *
 	 * @param   EndToEndTester $I  Tester.
 	 */
@@ -101,10 +101,15 @@ public function testMC4WPImportWithBlocks(EndToEndTester $I)
 		$I->waitForElementVisible('.notice-success');
 		$I->see('MC4WP forms migrated successfully.');
 
-		// View the Pages, to confirm Kit Forms now display.
+		// 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;*()_+\\');
 		}
 	}
 
@@ -257,7 +262,16 @@ private function _createPagesWithMC4WPBlocks(EndToEndTester $I, $mc4wpFormIDs)
 					'post_type'    => 'page',
 					'post_status'  => 'publish',
 					'post_title'   => 'Page with MC4WP Block #' . $mc4wpFormID,
-					'post_content' => '<!-- wp:mailchimp-for-wp/form {"id":' . $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'          => '',
+						],
+					],
 				]
 			);
 		}
diff --git a/tests/Integration/ImporterTest.php b/tests/Integration/ImporterTest.php
index 6ce2175ee..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.
 	 *
@@ -154,11 +163,12 @@ public function testAWeberReplaceShortcodesInContentIgnoringOtherShortcodes()
 	}
 
 	/**
-	 * Test that the replace_blocks_in_content() method replaces the third party form block with the Kit form block.
+	 * 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   3.1.5
+	 * @since   3.1.6
 	 */
-	public function testAWeberReplaceBlocksInContent()
+	public function testAWeberReplaceBlocksInPost()
 	{
 		// Initialize the class we want to test.
 		$this->importer = new \ConvertKit_Admin_Importer_AWeber();
@@ -166,24 +176,39 @@ public function testAWeberReplaceBlocksInContent()
 		// 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"} -->
+		// 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 -->';
+<!-- /wp:aweber-signupform-block/aweber-shortcode -->' . $this->html_block
+				),
+			]
+		);
 
-		// Test the block is replaced with the Kit form 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->importer->replace_blocks_in_content( $content, 289586845, $_ENV['CONVERTKIT_API_FORM_ID'] )
+			'<!-- 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 ignores non-AWeber blocks.
+	 * 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   3.1.5
+	 * @since   3.1.6
 	 */
-	public function testAWeberReplaceBlocksInContentIgnoringOtherBlocks()
+	public function testAWeberReplaceBlocksInContent()
 	{
 		// Initialize the class we want to test.
 		$this->importer = new \ConvertKit_Admin_Importer_AWeber();
@@ -192,15 +217,14 @@ public function testAWeberReplaceBlocksInContentIgnoringOtherBlocks()
 		$this->assertNotInstanceOf(\WP_Error::class, $this->importer);
 
 		// Define the blocks to test.
-		$html_block = '<!-- wp:html --><div class="wp-block-core-html">Some content</div><!-- /wp:html -->';
-		$content    = '<!-- wp:aweber-signupform-block/aweber-shortcode {"selectedShortCode":"6924484-289586845-webform"} -->
+		$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 -->' . $html_block;
+<!-- /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'] . '"} /-->' . $html_block,
-			$this->importer->replace_blocks_in_content( $content, 289586845, $_ENV['CONVERTKIT_API_FORM_ID'] )
+			'<!-- 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'] )
 		);
 	}
 
@@ -309,11 +333,12 @@ public function testMC4WPReplaceShortcodesInContentIgnoringOtherShortcodes()
 	}
 
 	/**
-	 * Test that the replace_blocks_in_content() method replaces the third party form block with the Kit form block.
+	 * 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   3.1.5
+	 * @since   3.1.6
 	 */
-	public function testMC4WPReplaceBlocksInContent()
+	public function testMC4WPReplaceBlocksInPost()
 	{
 		// Initialize the class we want to test.
 		$this->importer = new \ConvertKit_Admin_Importer_MC4WP();
@@ -321,22 +346,33 @@ public function testMC4WPReplaceBlocksInContent()
 		// 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} /-->';
+		// 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 ),
+			]
+		);
 
-		// Test the block is replaced with the Kit form 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->importer->replace_blocks_in_content( $content, 4410, $_ENV['CONVERTKIT_API_FORM_ID'] )
+			'<!-- 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 ignores non-MC4WP blocks.
+	 * 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   3.1.5
+	 * @since   3.1.6
 	 */
-	public function testMC4WPReplaceBlocksInContentIgnoringOtherBlocks()
+	public function testMC4WPReplaceBlocksInContent()
 	{
 		// Initialize the class we want to test.
 		$this->importer = new \ConvertKit_Admin_Importer_MC4WP();
@@ -345,13 +381,12 @@ public function testMC4WPReplaceBlocksInContentIgnoringOtherBlocks()
 		$this->assertNotInstanceOf(\WP_Error::class, $this->importer);
 
 		// Define the blocks to test.
-		$html_block = '<!-- wp:html --><div class="wp-block-core-html">Some content</div><!-- /wp:html -->';
-		$content    = '<!-- wp:mailchimp-for-wp/form {"id":4410} /-->' . $html_block;
+		$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'] . '"} /-->' . $html_block,
-			$this->importer->replace_blocks_in_content( $content, 4410, $_ENV['CONVERTKIT_API_FORM_ID'] )
+			'<!-- 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'] )
 		);
 	}
 }