diff --git a/admin/importers/class-convertkit-admin-importer-convertkit-legacy-forms.php b/admin/importers/class-convertkit-admin-importer-convertkit-legacy-forms.php
new file mode 100644
index 000000000..fc491d34a
--- /dev/null
+++ b/admin/importers/class-convertkit-admin-importer-convertkit-legacy-forms.php
@@ -0,0 +1,280 @@
+<?php
+/**
+ * ConvertKit Admin Importer Kit Legacy Forms class.
+ *
+ * @package ConvertKit
+ * @author ConvertKit
+ */
+
+/**
+ * Import and migrate data from Kit Legacy Forms to Kit.
+ *
+ * @package ConvertKit
+ * @author ConvertKit
+ */
+class ConvertKit_Admin_Importer_ConvertKit_Legacy_Forms extends ConvertKit_Admin_Importer {
+
+	/**
+	 * Holds the programmatic name of the importer (lowercase, no spaces).
+	 *
+	 * @since   3.3.5
+	 *
+	 * @var     string
+	 */
+	public $name = 'convertkit_legacy_forms';
+
+	/**
+	 * Holds the title of the importer (for display in the importer list).
+	 *
+	 * @since   3.3.5
+	 *
+	 * @var     string
+	 */
+	public $title = 'Kit Legacy Forms';
+
+	/**
+	 * Holds the shortcode name for ConvertKit Legacy Forms.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @var     string
+	 */
+	public $shortcode_name = 'convertkit_form';
+
+	/**
+	 * Holds the ID attribute names for Kit Legacy Form shortcodes.
+	 *
+	 * Both `form` and `id` are matched because Kit's `[convertkit_form]`
+	 * shortcode has supported both attribute names historically.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @var     array
+	 */
+	public $shortcode_id_attribute = array( 'form', 'id' );
+
+	/**
+	 * Holds the block name for ConvertKit Legacy Forms.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @var     string
+	 */
+	public $block_name = 'convertkit/form';
+
+	/**
+	 * Holds the ID attribute names for Kit Legacy Form blocks.
+	 *
+	 * Both `form` and `id` are matched because Kit's form block has supported
+	 * both attribute names historically.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @var     array
+	 */
+	public $block_id_attribute = array( 'form', 'id' );
+
+	/**
+	 * Constructor
+	 *
+	 * @since   3.3.5
+	 */
+	public function __construct() {
+
+		// Define a custom description for this importer.
+		$this->description = __( 'Kit Legacy Forms are being phased out. Use this tool to replace Kit Form shortcodes and blocks using a Legacy Form with a new Kit Form.', 'convertkit' );
+
+		// Register this as an importer, if ConvertKit Legacy Forms exist.
+		add_filter( 'convertkit_get_form_importers', array( $this, 'register' ) );
+
+	}
+
+	/**
+	 * Returns an array of Kit Legacy Forms form IDs and titles.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @return  array
+	 */
+	public function get_forms() {
+
+		// Query resource class to fetch legacy forms.
+		$forms            = array();
+		$convertkit_forms = new ConvertKit_Resource_Forms( 'settings' );
+		if ( $convertkit_forms->exist() ) {
+			foreach ( $convertkit_forms->get() as $form ) {
+				// Skip if not a Legacy Form.
+				if ( ! $convertkit_forms->is_legacy( $form['id'] ) ) {
+					continue;
+				}
+
+				$forms[ $form['id'] ] = $form['name'];
+			}
+		}
+
+		return $forms;
+
+	}
+
+	/**
+	 * Returns an array of legacy Kit form IDs (as strings) for use in
+	 * filtering shortcodes/blocks that reference them.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @return  array
+	 */
+	private function get_legacy_form_ids() {
+
+		$legacy_ids       = array();
+		$convertkit_forms = new ConvertKit_Resource_Forms( 'settings' );
+
+		if ( ! $convertkit_forms->exist() ) {
+			return $legacy_ids;
+		}
+
+		foreach ( $convertkit_forms->get() as $form ) {
+			if ( ! $convertkit_forms->is_legacy( $form['id'] ) ) {
+				continue;
+			}
+			$legacy_ids[] = (string) $form['id'];
+		}
+
+		return $legacy_ids;
+
+	}
+
+	/**
+	 * Overrides the parent method to:
+	 * - return form IDs found in both shortcodes AND blocks (the parent only
+	 *   handles shortcodes), and
+	 * - filter the result so only legacy form IDs are returned.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @param   string $content    Content containing Kit Form shortcodes / blocks.
+	 * @return  array
+	 */
+	public function get_form_ids_from_content( $content ) {
+
+		// Get shortcode-derived form IDs from the parent.
+		$shortcode_ids = parent::get_form_ids_from_content( $content );
+
+		// Get block-derived form IDs (parent only handles shortcodes).
+		$block_ids = $this->get_block_form_ids_from_content( $content );
+
+		// Combine and filter to legacy form IDs only.
+		$all_ids    = array_unique( array_merge( $shortcode_ids, $block_ids ) );
+		$legacy_ids = $this->get_legacy_form_ids();
+
+		// Cast both sides to strings for safe comparison.
+		$all_ids = array_map( 'strval', $all_ids );
+
+		return array_values( array_intersect( $all_ids, $legacy_ids ) );
+
+	}
+
+	/**
+	 * Returns an array of form IDs from convertkit/form blocks in the given
+	 * content. Walks innerBlocks recursively.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @param   string $content    Content containing Kit Form blocks.
+	 * @return  array
+	 */
+	private function get_block_form_ids_from_content( $content ) {
+
+		return $this->extract_block_form_ids( parse_blocks( $content ) );
+
+	}
+
+	/**
+	 * Recursively walks blocks (and innerBlocks) and returns an array of form
+	 * IDs from any convertkit/form block's `form` attribute.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @param   array $blocks    Blocks.
+	 * @return  array
+	 */
+	private function extract_block_form_ids( $blocks ) {
+
+		$form_ids = array();
+
+		// Normalise the block ID attribute(s) to an array so we can match
+		// against multiple attribute names (e.g. both `form` and `id`).
+		$id_attributes = (array) $this->block_id_attribute;
+
+		foreach ( $blocks as $block ) {
+			if ( ! empty( $block['innerBlocks'] ) ) {
+				$form_ids = array_merge(
+					$form_ids,
+					$this->extract_block_form_ids( $block['innerBlocks'] )
+				);
+			}
+
+			if ( $block['blockName'] !== $this->block_name ) {
+				continue;
+			}
+
+			// Record the form ID from the first matching attribute. If a block
+			// somehow has both `form` and `id` set, they'd be the same value, so
+			// we stop after the first match to avoid double-counting.
+			foreach ( $id_attributes as $id_attribute ) {
+				if ( empty( $block['attrs'][ $id_attribute ] ) ) {
+					continue;
+				}
+				$form_ids[] = (string) $block['attrs'][ $id_attribute ];
+				break;
+			}
+		}
+
+		return $form_ids;
+
+	}
+
+	/**
+	 * Overrides the parent method to only return post IDs whose content
+	 * contains a Kit Form shortcode or block referencing a legacy form ID.
+	 *
+	 * The parent's broad SQL match returns any post containing a
+	 * `[convertkit_form` shortcode or `<!-- wp:convertkit/form` block, which
+	 * for the Kit Legacy Forms importer is too broad: non-legacy uses of these
+	 * shortcodes/blocks are valid and should not appear in the importer UI.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @return  array
+	 */
+	public function get_forms_in_posts() {
+
+		$candidate_post_ids = parent::get_forms_in_posts();
+
+		if ( empty( $candidate_post_ids ) ) {
+			return array();
+		}
+
+		$legacy_ids = $this->get_legacy_form_ids();
+		if ( empty( $legacy_ids ) ) {
+			return array();
+		}
+
+		$matched_post_ids = array();
+		foreach ( $candidate_post_ids as $post_id ) {
+			$content = get_post_field( 'post_content', $post_id );
+
+			// get_form_ids_from_content() (overridden above) returns only legacy IDs
+			// from both shortcodes and blocks, so any non-empty result means this
+			// post contains at least one legacy form reference.
+			$legacy_form_ids_in_content = $this->get_form_ids_from_content( $content );
+			if ( ! empty( $legacy_form_ids_in_content ) ) {
+				$matched_post_ids[] = $post_id;
+			}
+		}
+
+		return $matched_post_ids;
+
+	}
+
+}
diff --git a/admin/importers/class-convertkit-admin-importer.php b/admin/importers/class-convertkit-admin-importer.php
index 174b4eac6..611ee5a60 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 $title = '';
 
+	/**
+	 * Holds the importer description.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @var     string
+	 */
+	public $description = '';
+
 	/**
 	 * Holds the shortcode name for the third party Form plugin.
 	 *
@@ -42,11 +51,15 @@ abstract class ConvertKit_Admin_Importer {
 	public $shortcode_name = '';
 
 	/**
-	 * Holds the shortcode ID attribute name for the third party Form plugin.
+	 * Holds the shortcode ID attribute name(s) for the third party Form plugin.
+	 *
+	 * Accepts a string for a single attribute (e.g. 'form'), or an array of
+	 * strings for plugins where the form ID may appear under multiple attribute
+	 * names (e.g. ['form', 'id']).
 	 *
 	 * @since   3.1.0
 	 *
-	 * @var     bool|string
+	 * @var     bool|string|array
 	 */
 	public $shortcode_id_attribute = false;
 
@@ -60,11 +73,15 @@ abstract class ConvertKit_Admin_Importer {
 	public $block_name = '';
 
 	/**
-	 * Holds the block ID attribute name for the third party Form plugin.
+	 * Holds the block ID attribute name(s) for the third party Form plugin.
+	 *
+	 * Accepts a string for a single attribute (e.g. 'form'), or an array of
+	 * strings for plugins where the form ID may appear under multiple attribute
+	 * names (e.g. ['form', 'id']).
 	 *
 	 * @since   3.1.6
 	 *
-	 * @var     bool|string
+	 * @var     bool|string|array
 	 */
 	public $block_id_attribute = false;
 
@@ -99,9 +116,10 @@ public function register( $importers ) {
 
 		// Add this importer to the list of importers.
 		$importers[ $this->name ] = array(
-			'name'  => $this->name,
-			'title' => $this->title,
-			'forms' => $this->get_forms(),
+			'name'        => $this->name,
+			'title'       => $this->title,
+			'description' => $this->description,
+			'forms'       => $this->get_forms(),
 		);
 
 		return $importers;
@@ -276,21 +294,36 @@ public function replace_shortcodes_in_content( $content, $third_party_form_id, $
 			$pattern = '/\['                                     // Start regex with an opening square bracket.
 			. preg_quote( $this->shortcode_name, '/' )       // Match the shortcode name, escaping any regex special chars.
 			. '[^\]]*?\]/i';                                 // Match any other characters (non-greedy) up to the closing square bracket, case-insensitive.
-		} else {
+
+			return preg_replace(
+				$pattern,
+				'[convertkit_form form="' . $form_id . '"]',
+				$content
+			);
+		}
+
+		// Normalise the shortcode ID attribute to an array, so importers can
+		// declare a single attribute (string) or multiple attributes (array).
+		$id_attributes = (array) $this->shortcode_id_attribute;
+
+		// Run a replacement pass per attribute name.
+		foreach ( $id_attributes as $id_attribute ) {
 			$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.
+				. '\b' . preg_quote( $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, '/' ) . '\'|' . preg_quote( (string) $third_party_form_id, '/' ) . ')' // Match the form ID, double quotes, single quotes or unquoted.
 				. '[^\]]*?\]/i';                                 // Match any other characters (non-greedy) up to the closing square bracket, case-insensitive.
+
+			$content = preg_replace(
+				$pattern,
+				'[convertkit_form form="' . $form_id . '"]',
+				$content
+			);
 		}
 
-		return preg_replace(
-			$pattern,
-			'[convertkit_form id="' . $form_id . '"]',
-			$content
-		);
+		return $content;
 
 	}
 
@@ -359,29 +392,37 @@ public function get_form_ids_from_content( $content ) {
 			return array();
 		}
 
-		// Legacy: Extract where attribute is required.
-		$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 double quoted, single quoted or unquoted value.
-			. '[^\]]*?\]/i';                                   // Match up to closing bracket, case-insensitive.
+		// Normalise the shortcode ID attribute to an array, so importers can
+		// declare a single attribute (string) or multiple attributes (array).
+		$id_attributes = (array) $this->shortcode_id_attribute;
 
-		preg_match_all( $pattern, $content, $matches );
+		// Extract form IDs, running a match pass per attribute name.
+		$form_ids = array();
+		foreach ( $id_attributes as $id_attribute ) {
+			$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( $id_attribute, '/' )                 // Match the id attribute name.
+				. '\s*=\s*'                                        // Optional whitespace, equals sign, optional whitespace.
+				. '(?:"([^"]+)"|\'([^\']+)\'|([^\s\]]+))'          // Capture double quoted, single quoted or unquoted value.
+				. '[^\]]*?\]/i';                                   // Match up to closing bracket, case-insensitive.
 
-		// Extract form IDs: They could be in either $matches[1] (double quoted), $matches[2] (single quoted) or $matches[3] (unquoted).
-		$form_ids = array_values(
-			array_filter(
-				array_merge(
-					isset( $matches[1] ) ? $matches[1] : array(),
-					isset( $matches[2] ) ? $matches[2] : array(),
-					isset( $matches[3] ) ? $matches[3] : array()
+			preg_match_all( $pattern, $content, $matches );
+
+			// Extract form IDs: They could be in either $matches[1] (double quoted), $matches[2] (single quoted) or $matches[3] (unquoted).
+			$form_ids = array_merge(
+				$form_ids,
+				array_filter(
+					array_merge(
+						isset( $matches[1] ) ? $matches[1] : array(),
+						isset( $matches[2] ) ? $matches[2] : array(),
+						isset( $matches[3] ) ? $matches[3] : array()
+					)
 				)
-			)
-		);
+			);
+		}
 
-		return $form_ids;
+		return array_values( array_unique( $form_ids ) );
 
 	}
 
@@ -504,13 +545,27 @@ private function recursively_convert_blocks( $blocks, $third_party_form_id, $for
 			// If the block ID attribute is not set, the third party Plugin doesn't use IDs,
 			// so there's no need to check the $third_party_form_id matches the block attribute.
 			if ( $this->block_id_attribute ) {
-				// 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;
+				// Normalise the block ID attribute to an array, so importers can
+				// declare a single attribute (string) or multiple attributes (array).
+				$id_attributes = (array) $this->block_id_attribute;
+
+				// Check if at least one attribute contains the third party form ID.
+				$matched = false;
+				foreach ( $id_attributes as $id_attribute ) {
+					if ( ! array_key_exists( $id_attribute, $block['attrs'] ) ) {
+						continue;
+					}
+
+					if ( stripos( $block['attrs'][ $id_attribute ], (string) $third_party_form_id ) === false ) {
+						continue;
+					}
+
+					$matched = true;
+					break;
 				}
 
-				// 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 ) {
+				// Skip if none of the configured ID attributes match.
+				if ( ! $matched ) {
 					continue;
 				}
 			}
diff --git a/admin/section/class-convertkit-admin-section-tools.php b/admin/section/class-convertkit-admin-section-tools.php
index e5524230a..e95767f2b 100644
--- a/admin/section/class-convertkit-admin-section-tools.php
+++ b/admin/section/class-convertkit-admin-section-tools.php
@@ -60,6 +60,7 @@ public function register_notices( $notices ) {
 				'migrate_activecampaign_configuration_success' => __( 'ActiveCampaign forms migrated successfully.', 'convertkit' ),
 				'migrate_aweber_configuration_success'     => __( 'AWeber forms migrated successfully.', 'convertkit' ),
 				'migrate_campaignmonitor_configuration_success' => __( 'Campaign Monitor forms migrated successfully.', 'convertkit' ),
+				'migrate_convertkit_legacy_forms_configuration_success' => __( 'Kit Legacy Forms migrated successfully.', 'convertkit' ),
 				'migrate_mc4wp_configuration_success'      => __( 'MC4WP forms migrated successfully.', 'convertkit' ),
 				'migrate_mailpoet_configuration_success'   => __( 'MailPoet forms migrated successfully.', 'convertkit' ),
 				'migrate_newsletter_configuration_success' => __( 'Newsletter forms migrated successfully.', 'convertkit' ),
diff --git a/includes/class-wp-convertkit.php b/includes/class-wp-convertkit.php
index 9e49cc858..659974839 100644
--- a/includes/class-wp-convertkit.php
+++ b/includes/class-wp-convertkit.php
@@ -79,23 +79,24 @@ private function initialize_admin() {
 			return;
 		}
 
-		$this->classes['admin_bulk_edit']                     = new ConvertKit_Admin_Bulk_Edit();
-		$this->classes['admin_cache_plugins']                 = new ConvertKit_Admin_Cache_Plugins();
-		$this->classes['admin_category']                      = new ConvertKit_Admin_Category();
-		$this->classes['admin_landing_page']                  = new ConvertKit_Admin_Landing_Page();
-		$this->classes['admin_importer_activecampaign']       = new ConvertKit_Admin_Importer_ActiveCampaign();
-		$this->classes['admin_importer_aweber']               = new ConvertKit_Admin_Importer_AWeber();
-		$this->classes['admin_importer_campaignmonitor']      = new ConvertKit_Admin_Importer_CampaignMonitor();
-		$this->classes['admin_importer_mc4wp']                = new ConvertKit_Admin_Importer_MC4WP();
-		$this->classes['admin_importer_mailpoet']             = new ConvertKit_Admin_Importer_Mailpoet();
-		$this->classes['admin_importer_newsletter']           = new ConvertKit_Admin_Importer_Newsletter();
-		$this->classes['admin_post']                          = new ConvertKit_Admin_Post();
-		$this->classes['admin_quick_edit']                    = new ConvertKit_Admin_Quick_Edit();
-		$this->classes['admin_restrict_content']              = new ConvertKit_Admin_Restrict_Content();
-		$this->classes['admin_settings']                      = new ConvertKit_Admin_Settings();
-		$this->classes['admin_setup_wizard_landing_page']     = new ConvertKit_Admin_Setup_Wizard_Landing_Page();
-		$this->classes['admin_setup_wizard_plugin']           = new ConvertKit_Admin_Setup_Wizard_Plugin();
-		$this->classes['admin_setup_wizard_restrict_content'] = new ConvertKit_Admin_Setup_Wizard_Restrict_Content();
+		$this->classes['admin_bulk_edit']                        = new ConvertKit_Admin_Bulk_Edit();
+		$this->classes['admin_cache_plugins']                    = new ConvertKit_Admin_Cache_Plugins();
+		$this->classes['admin_category']                         = new ConvertKit_Admin_Category();
+		$this->classes['admin_landing_page']                     = new ConvertKit_Admin_Landing_Page();
+		$this->classes['admin_importer_activecampaign']          = new ConvertKit_Admin_Importer_ActiveCampaign();
+		$this->classes['admin_importer_aweber']                  = new ConvertKit_Admin_Importer_AWeber();
+		$this->classes['admin_importer_campaignmonitor']         = new ConvertKit_Admin_Importer_CampaignMonitor();
+		$this->classes['admin_importer_convertkit_legacy_forms'] = new ConvertKit_Admin_Importer_ConvertKit_Legacy_Forms();
+		$this->classes['admin_importer_mc4wp']                   = new ConvertKit_Admin_Importer_MC4WP();
+		$this->classes['admin_importer_mailpoet']                = new ConvertKit_Admin_Importer_Mailpoet();
+		$this->classes['admin_importer_newsletter']              = new ConvertKit_Admin_Importer_Newsletter();
+		$this->classes['admin_post']                             = new ConvertKit_Admin_Post();
+		$this->classes['admin_quick_edit']                       = new ConvertKit_Admin_Quick_Edit();
+		$this->classes['admin_restrict_content']                 = new ConvertKit_Admin_Restrict_Content();
+		$this->classes['admin_settings']                         = new ConvertKit_Admin_Settings();
+		$this->classes['admin_setup_wizard_landing_page']        = new ConvertKit_Admin_Setup_Wizard_Landing_Page();
+		$this->classes['admin_setup_wizard_plugin']              = new ConvertKit_Admin_Setup_Wizard_Plugin();
+		$this->classes['admin_setup_wizard_restrict_content']    = new ConvertKit_Admin_Setup_Wizard_Restrict_Content();
 
 		/**
 		 * Initialize integration classes for the WordPress Administration interface.
diff --git a/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterKitLegacyFormsCest.php b/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterKitLegacyFormsCest.php
new file mode 100644
index 000000000..f8ed99e6d
--- /dev/null
+++ b/tests/EndToEnd/general/plugin-screens/PluginSettingsToolsImporterKitLegacyFormsCest.php
@@ -0,0 +1,230 @@
+<?php
+
+namespace Tests\EndToEnd;
+
+use Tests\Support\EndToEndTester;
+
+/**
+ * Tests for the Settings > Kit > Tools > Import sections for Kit Legacy Forms.
+ *
+ * @since   3.3.5
+ */
+class PluginSettingsToolsImporterKitLegacyFormsCest
+{
+	/**
+	 * Run common actions before running the test functions in this class.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @param   EndToEndTester $I  Tester.
+	 */
+	public function _before(EndToEndTester $I)
+	{
+		// Activate Plugin.
+		$I->activateKitPlugin($I);
+	}
+
+	/**
+	 * Test that Kit Legacy Form Shortcodes are replaced with Kit Form Shortcodes when the Tools > Kit Legacy Forms: Migrate Configuration is configured.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @param   EndToEndTester $I  Tester.
+	 */
+	public function testKitLegacyFormsImportWithShortcodes(EndToEndTester $I)
+	{
+		// Setup Plugin.
+		$I->setupKitPlugin($I);
+		$I->setupKitPluginResources($I);
+
+		// Insert Kit Legacy Form Shortcode into Page.
+		$pageID = $this->_createPageWithKitLegacyFormShortcodes($I, $_ENV['CONVERTKIT_API_LEGACY_FORM_ID']);
+
+		// Navigate to the Tools screen.
+		$I->loadKitSettingsToolsScreen($I);
+
+		// Select the Kit Form to replace the Kit Legacy Form.
+		$I->selectOption('_wp_convertkit_integration_convertkit_legacy_forms_settings[' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . ']', $_ENV['CONVERTKIT_API_FORM_ID']);
+
+		// Click the Migrate button.
+		$I->click('Migrate');
+
+		// Confirm success message displays.
+		$I->waitForElementVisible('.notice-success');
+		$I->see('Kit Legacy Forms migrated successfully.');
+
+		// View the Page, to confirm Kit Form now displays.
+		$I->amOnPage('?p=' . $pageID);
+		$I->seeElementInDOM('form[data-sv-form]');
+	}
+
+	/**
+	 * Test that Kit Legacy Form Blocks are replaced with Kit Blocks when the Tools > Kit Legacy Forms: Migrate Configuration is configured.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @param   EndToEndTester $I  Tester.
+	 */
+	public function testKitLegacyFormsImportWithBlocks(EndToEndTester $I)
+	{
+		// Setup Plugin.
+		$I->setupKitPlugin($I);
+		$I->setupKitPluginResources($I);
+
+		// Insert Kit Legacy Form Block into Page.
+		$pageID = $this->_createPageWithKitLegacyFormBlocks($I, $_ENV['CONVERTKIT_API_LEGACY_FORM_ID']);
+
+		// Navigate to the Tools screen.
+		$I->loadKitSettingsToolsScreen($I);
+
+		// Select the Kit Form to replace the Kit Legacy Form.
+		$I->selectOption('_wp_convertkit_integration_convertkit_legacy_forms_settings[' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . ']', $_ENV['CONVERTKIT_API_FORM_ID']);
+
+		// Click the Migrate button.
+		$I->click('Migrate');
+
+		// Confirm success message displays.
+		$I->waitForElementVisible('.notice-success');
+		$I->see('Kit Legacy Forms migrated successfully.');
+
+		// View the Page, to confirm Kit Form block now displays.
+		$I->amOnPage('?p=' . $pageID);
+		$I->seeElementInDOM('form[data-sv-form]');
+
+		// Confirm special characters have not been stripped.
+		$I->seeInSource('!@£$%^&amp;*()_+~!@£$%^&amp;*()_+\\');
+	}
+
+	/**
+	 * Test that the Kit Legacy Forms: Migrate Configuration section is not displayed when no Kit Legacy Forms exist.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @param   EndToEndTester $I  Tester.
+	 */
+	public function testKitLegacyFormsImportWhenNoKitLegacyForms(EndToEndTester $I)
+	{
+		// Setup Plugin.
+		$I->setupKitPlugin($I);
+
+		// Navigate to the Tools screen.
+		$I->loadKitSettingsToolsScreen($I);
+
+		// Confirm no Kit Legacy Forms: Migrate Configuration section is displayed.
+		$I->dontSeeElementInDOM('#import-kit-legacy-forms');
+	}
+
+	/**
+	 * Test that the Kit Legacy Forms: Migrate Configuration section is not displayed when Kit Legacy Forms exist,
+	 * but no Pages, Posts or Custom Posts contain Kit Legacy Form Shortcodes.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @param   EndToEndTester $I  Tester.
+	 */
+	public function testKitLegacyFormsImportWhenNoKitLegacyShortcodesOrBlocksInContent(EndToEndTester $I)
+	{
+		// Setup Plugin.
+		$I->setupKitPlugin($I);
+		$I->setupKitPluginResources($I);
+
+		// Navigate to the Tools screen.
+		$I->loadKitSettingsToolsScreen($I);
+
+		// Confirm no Kit Legacy Forms: Migrate Configuration section is displayed, as there are no
+		// Kit Legacy Form Shortcodes or Blocks in the content.
+		$I->dontSeeElementInDOM('#import-kit-legacy-forms');
+	}
+
+	/**
+	 * Test that the Kit Legacy Forms: Migrate Configuration section is not displayed when no Kit Forms exist.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @param   EndToEndTester $I  Tester.
+	 */
+	public function testKitLegacyFormsImportWhenNoKitForms(EndToEndTester $I)
+	{
+		// Setup Plugin.
+		$I->setupKitPluginCredentialsNoData($I);
+		$I->setupKitPluginResourcesNoData($I);
+
+		// Navigate to the Tools screen.
+		$I->loadKitSettingsToolsScreen($I);
+
+		// Confirm no Kit Legacy Forms: Migrate Configuration section is displayed, as there are no
+		// Kit Forms exist.
+		$I->dontSeeElementInDOM('#import-kit-legacy-forms');
+	}
+
+	/**
+	 * Create Pages with Kit Legacy Form Shortcodes.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @param   EndToEndTester $I  Tester.
+	 * @param   int            $kitLegacyFormID  Kit Legacy Form ID.
+	 * @return  int
+	 */
+	private function _createPageWithKitLegacyFormShortcodes(EndToEndTester $I, $kitLegacyFormID)
+	{
+		return $I->havePostInDatabase(
+			[
+				'post_type'    => 'page',
+				'post_status'  => 'publish',
+				'post_title'   => 'Page with Kit Form Shortcode using Legacy Form #' . $kitLegacyFormID,
+				'post_content' => '[convertkit_form form="' . $kitLegacyFormID . '"]',
+				'meta_input'   => [
+					'_wp_convertkit_post_meta' => [
+						'form'         => '0',
+						'landing_page' => '',
+						'tag'          => '',
+					],
+				],
+			]
+		);
+	}
+
+	/**
+	 * Create Pages with Kit Legacy Form Blocks.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @param   EndToEndTester $I  Tester.
+	 * @param   int            $kitLegacyFormID  Kit Legacy Form ID.
+	 * @return  int
+	 */
+	private function _createPageWithKitLegacyFormBlocks(EndToEndTester $I, $kitLegacyFormID)
+	{
+		return $I->havePostInDatabase(
+			[
+				'post_type'    => 'page',
+				'post_status'  => 'publish',
+				'post_title'   => 'Page with Kit Form Block using Legacy Form #' . $kitLegacyFormID,
+				'post_content' => '<!-- wp:convertkit/form {"form":' . $kitLegacyFormID . '} /--><!-- wp:html --><div class="wp-block-core-html">Some content with characters !@£$%^&amp;*()_+~!@£$%^&amp;*()_+\\\</div><!-- /wp:html -->',
+				'meta_input'   => [
+					'_wp_convertkit_post_meta' => [
+						'form'         => '0',
+						'landing_page' => '',
+						'tag'          => '',
+					],
+				],
+			]
+		);
+	}
+
+	/**
+	 * 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
+	 * deactivation and not the true test error.
+	 *
+	 * @since   3.3.5
+	 *
+	 * @param   EndToEndTester $I  Tester.
+	 */
+	public function _passed(EndToEndTester $I)
+	{
+		$I->deactivateKitPlugin($I);
+		$I->resetKitPlugin($I);
+	}
+}
diff --git a/tests/Integration/ImporterTest.php b/tests/Integration/ImporterTest.php
index c11f99668..7ebbc08df 100644
--- a/tests/Integration/ImporterTest.php
+++ b/tests/Integration/ImporterTest.php
@@ -38,6 +38,126 @@ public function setUp(): void
 
 		// Activate Plugin.
 		activate_plugins('convertkit/wp-convertkit.php');
+
+		// Define Forms as if the Forms resource class populated them from the API.
+		update_option(
+			'convertkit_forms',
+			[
+				3059218 => [
+					'id'         => 3059218,
+					'name'       => 'Auto Confirm Form',
+					'created_at' => '2022-03-07T15:57:51Z',
+					'type'       => 'embed',
+					'format'     => 'inline',
+					'embed_js'   => 'https://cheerful-architect-3237.kit.com/bfac9ed794/index.js',
+					'embed_url'  => 'https://cheerful-architect-3237.kit.com/bfac9ed794',
+					'archived'   => false,
+					'uid'        => 'bfac9ed794',
+				],
+				2765143 => [
+					'id'         => 2765143,
+					'name'       => 'Double Optin Form',
+					'created_at' => '2021-11-11T15:31:28Z',
+					'type'       => 'embed',
+					'format'     => 'inline',
+					'embed_js'   => 'https://cheerful-architect-3237.kit.com/a04b384fc6/index.js',
+					'embed_url'  => 'https://cheerful-architect-3237.kit.com/a04b384fc6',
+					'archived'   => false,
+					'uid'        => 'a04b384fc6',
+				],
+				3003590 => [
+					'id'         => 3003590,
+					'name'       => 'Third Party Integrations Form',
+					'created_at' => '2022-02-17T15:05:31.000Z',
+					'type'       => 'embed',
+					'format'     => 'inline',
+					'embed_js'   => 'https://cheerful-architect-3237.kit.com/71cbcc4042/index.js',
+					'embed_url'  => 'https://cheerful-architect-3237.kit.com/71cbcc4042',
+					'archived'   => false,
+					'uid'        => '71cbcc4042',
+				],
+				2780977 => [
+					'id'         => 2780977,
+					'name'       => 'Modal Form',
+					'created_at' => '2021-11-17T04:22:06.000Z',
+					'type'       => 'embed',
+					'format'     => 'modal',
+					'embed_js'   => 'https://cheerful-architect-3237.kit.com/397e876257/index.js',
+					'embed_url'  => 'https://cheerful-architect-3237.kit.com/397e876257',
+					'archived'   => false,
+					'uid'        => '397e876257',
+				],
+				2780979 => [
+					'id'         => 2780979,
+					'name'       => 'Slide In Form',
+					'created_at' => '2021-11-17T04:22:24.000Z',
+					'type'       => 'embed',
+					'format'     => 'slide in',
+					'embed_js'   => 'https://cheerful-architect-3237.kit.com/e0d65bed9d/index.js',
+					'embed_url'  => 'https://cheerful-architect-3237.kit.com/e0d65bed9d',
+					'archived'   => false,
+					'uid'        => 'e0d65bed9d',
+				],
+				2765139 => [
+					'id'         => 2765139,
+					'name'       => 'Page Form',
+					'created_at' => '2021-11-11T15:30:40.000Z',
+					'type'       => 'embed',
+					'format'     => 'inline',
+					'embed_js'   => 'https://cheerful-architect-3237.kit.com/85629c512d/index.js',
+					'embed_url'  => 'https://cheerful-architect-3237.kit.com/85629c512d',
+					'archived'   => false,
+					'uid'        => '85629c512d',
+				],
+				470099  => [
+					'id'                  => 470099,
+					'name'                => 'Legacy Form',
+					'created_at'          => null,
+					'type'                => 'embed',
+					'url'                 => 'https://app.kit.com/landing_pages/470099',
+					'embed_js'            => 'https://api.kit.com/api/v3/forms/470099.js?api_key=' . $_ENV['CONVERTKIT_API_KEY'],
+					'embed_url'           => 'https://api.kit.com/api/v3/forms/470099.html?api_key=' . $_ENV['CONVERTKIT_API_KEY'],
+					'title'               => 'Join the newsletter',
+					'description'         => '<p>Subscribe to get our latest content by email.</p>',
+					'sign_up_button_text' => 'Subscribe',
+					'success_message'     => 'Success! Now check your email to confirm your subscription.',
+					'archived'            => false,
+				],
+				2780980 => [
+					'id'         => 2780980,
+					'name'       => 'Sticky Bar Form',
+					'created_at' => '2021-11-17T04:22:42.000Z',
+					'type'       => 'embed',
+					'format'     => 'sticky bar',
+					'embed_js'   => 'https://cheerful-architect-3237.kit.com/9f5c601482/index.js',
+					'embed_url'  => 'https://cheerful-architect-3237.kit.com/9f5c601482',
+					'archived'   => false,
+					'uid'        => '9f5c601482',
+				],
+				3437554 => [
+					'id'         => 3437554,
+					'name'       => 'AAA Test',
+					'created_at' => '2022-07-15T15:06:32.000Z',
+					'type'       => 'embed',
+					'format'     => 'inline',
+					'embed_js'   => 'https://cheerful-architect-3237.kit.com/3bb15822a2/index.js',
+					'embed_url'  => 'https://cheerful-architect-3237.kit.com/3bb15822a2',
+					'archived'   => false,
+					'uid'        => '3bb15822a2',
+				],
+				2765149 => [
+					'id'         => 2765149,
+					'name'       => 'WooCommerce Product Form',
+					'created_at' => '2021-11-11T15:32:54.000Z',
+					'type'       => 'embed',
+					'format'     => 'inline',
+					'embed_js'   => 'https://cheerful-architect-3237.kit.com/7e238f3920/index.js',
+					'embed_url'  => 'https://cheerful-architect-3237.kit.com/7e238f3920',
+					'archived'   => false,
+					'uid'        => '7e238f3920',
+				],
+			]
+		);
 	}
 
 	/**
@@ -53,6 +173,9 @@ public function tearDown(): void
 		// Deactivate Plugin.
 		deactivate_plugins('convertkit/wp-convertkit.php');
 
+		// Delete the Forms resource.
+		delete_option( 'convertkit_forms' );
+
 		parent::tearDown();
 	}
 
@@ -108,21 +231,21 @@ public function testActiveCampaignReplaceShortcodesInContent()
 		// Test each shortcode is replaced with the Kit form shortcode.
 		foreach ( $shortcodes as $shortcode ) {
 			$this->assertEquals(
-				'[convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 				$this->importer->replace_shortcodes_in_content( $shortcode, 1, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 
 			// Prepend and append some content.
 			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode.';
 			$this->assertEquals(
-				'Some content before the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode.',
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode.',
 				$this->importer->replace_shortcodes_in_content( $content, 1, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 
 			// Prepend and append some content and duplicate the shortcode.
 			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode: ' . $shortcode;
 			$this->assertEquals(
-				'Some content before the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 				$this->importer->replace_shortcodes_in_content( $content, 1, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 		}
@@ -143,7 +266,7 @@ public function testActiveCampaignReplaceShortcodesInContentIgnoringOtherShortco
 
 		// Define the shortcodes to test.
 		$shortcodes = [
-			'[convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+			'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 			'[a_random_shortcode]',
 		];
 
@@ -272,21 +395,21 @@ public function testAWeberReplaceShortcodesInContent()
 		// Test each shortcode is replaced with the Kit form shortcode.
 		foreach ( $shortcodes as $shortcode ) {
 			$this->assertEquals(
-				'[convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 				$this->importer->replace_shortcodes_in_content( $shortcode, 10, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 
 			// Prepend and append some content.
 			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode.';
 			$this->assertEquals(
-				'Some content before the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode.',
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode.',
 				$this->importer->replace_shortcodes_in_content( $content, 10, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 
 			// Prepend and append some content and duplicate the shortcode.
 			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode: ' . $shortcode;
 			$this->assertEquals(
-				'Some content before the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 				$this->importer->replace_shortcodes_in_content( $content, 10, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 		}
@@ -307,7 +430,7 @@ public function testAWeberReplaceShortcodesInContentIgnoringOtherShortcodes()
 
 		// Define the shortcodes to test.
 		$shortcodes = [
-			'[convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+			'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 			'[a_random_shortcode]',
 		];
 
@@ -435,21 +558,21 @@ public function testCampaignMonitorReplaceShortcodesInContent()
 		// Test each shortcode is replaced with the Kit form shortcode.
 		foreach ( $shortcodes as $shortcode ) {
 			$this->assertEquals(
-				'[convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 				$this->importer->replace_shortcodes_in_content( $shortcode, 'cm_6912dba75db2d', $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 
 			// Prepend and append some content.
 			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode.';
 			$this->assertEquals(
-				'Some content before the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode.',
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode.',
 				$this->importer->replace_shortcodes_in_content( $content, 'cm_6912dba75db2d', $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 
 			// Prepend and append some content and duplicate the shortcode.
 			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode: ' . $shortcode;
 			$this->assertEquals(
-				'Some content before the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 				$this->importer->replace_shortcodes_in_content( $content, 'cm_6912dba75db2d', $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 		}
@@ -470,7 +593,7 @@ public function testCampaignMonitorReplaceShortcodesInContentIgnoringOtherShortc
 
 		// Define the shortcodes to test.
 		$shortcodes = [
-			'[convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+			'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 			'[a_random_shortcode]',
 		];
 
@@ -483,6 +606,265 @@ public function testCampaignMonitorReplaceShortcodesInContentIgnoringOtherShortc
 		}
 	}
 
+	/**
+	 * Test that the get_form_ids_from_content() method returns Kit legacy form shortcode Form IDs
+	 * ignoring any other shortcodes.
+	 *
+	 * @since   3.3.5
+	 */
+	public function testGetKitLegacyFormsFormIDsFromContent()
+	{
+		// Initialize the class we want to test.
+		$this->importer = new \ConvertKit_Admin_Importer_ConvertKit_Legacy_Forms();
+
+		// Confirm initialization didn't result in an error.
+		$this->assertNotInstanceOf(\WP_Error::class, $this->importer);
+
+		// Define the content to test.
+		$content = 'Legacy Form: [convertkit_form form="' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . '"] Legacy Form ID: [convertkit_form id="' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . '"] non-Legacy Form: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Different shortcode: [aweber formid="12"]';
+
+		// Extract form IDs from content.
+		$form_ids = $this->importer->get_form_ids_from_content( $content );
+
+		// Assert the legacy form shortcode was detected, and the non-legacy form shortcode was ignored.
+		$this->assertEquals( 1, count( $form_ids ) );
+		$this->assertEquals( $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'], $form_ids[0] );
+	}
+
+	/**
+	 * Test that the replace_shortcodes_in_content() method replaces the Kit legacy form shortcode with the Kit form shortcode.
+	 *
+	 * @since   3.3.5
+	 */
+	public function testKitLegacyFormsReplaceShortcodesInContent()
+	{
+		// Initialize the class we want to test.
+		$this->importer = new \ConvertKit_Admin_Importer_ConvertKit_Legacy_Forms();
+
+		// Confirm initialization didn't result in an error.
+		$this->assertNotInstanceOf(\WP_Error::class, $this->importer);
+
+		// Define the shortcodes to test.
+		$shortcodes = [
+			'[convertkit_form form="' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . '"]',
+			'[convertkit_form form=' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . ']',
+			'[convertkit_form id="' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . '"]',
+			'[convertkit_form id=' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . ']',
+		];
+
+		// Test each shortcode is replaced with the Kit form shortcode.
+		foreach ( $shortcodes as $shortcode ) {
+			$this->assertEquals(
+				'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				$this->importer->replace_shortcodes_in_content( $shortcode, $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'], $_ENV['CONVERTKIT_API_FORM_ID'] )
+			);
+
+			// Prepend and append some content.
+			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode.';
+			$this->assertEquals(
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode.',
+				$this->importer->replace_shortcodes_in_content( $content, $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'], $_ENV['CONVERTKIT_API_FORM_ID'] )
+			);
+
+			// Prepend and append some content and duplicate the shortcode.
+			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode: ' . $shortcode;
+			$this->assertEquals(
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				$this->importer->replace_shortcodes_in_content( $content, $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'], $_ENV['CONVERTKIT_API_FORM_ID'] )
+			);
+		}
+	}
+
+	/**
+	 * Test that the replace_shortcodes_in_content() method ignores non-Kit legacy form shortcodes.
+	 *
+	 * @since   3.3.5
+	 */
+	public function testKitLegacyFormsReplaceShortcodesInContentIgnoringOtherShortcodes()
+	{
+		// Initialize the class we want to test.
+		$this->importer = new \ConvertKit_Admin_Importer_ConvertKit_Legacy_Forms();
+
+		// Confirm initialization didn't result in an error.
+		$this->assertNotInstanceOf(\WP_Error::class, $this->importer);
+
+		// Define the shortcodes to test.
+		$shortcodes = [
+			'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+			'[convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+			'[a_random_shortcode]',
+		];
+
+		// Test each shortcode is ignored.
+		foreach ( $shortcodes as $shortcode ) {
+			$this->assertEquals(
+				$shortcode,
+				$this->importer->replace_shortcodes_in_content( $shortcode, $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'], $_ENV['CONVERTKIT_API_FORM_ID'] )
+			);
+		}
+	}
+
+	/**
+	 * 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   3.3.5
+	 */
+	public function testKitLegacyFormsReplaceBlocksInPost()
+	{
+		// Initialize the class we want to test.
+		$this->importer = new \ConvertKit_Admin_Importer_ConvertKit_Legacy_Forms();
+
+		// 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'   => 'Kit Legacy Forms: Replace Blocks in Post',
+				'post_content' => str_replace( '\\', '\\\\', '<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . '"} /-->' . $this->html_block ),
+			]
+		);
+
+		// Replace the blocks in the post.
+		$this->importer->replace_blocks_in_post( $postID, $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'], $_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   3.3.5
+	 */
+	public function testKitLegacyFormsReplaceBlocksInContent()
+	{
+		// Initialize the class we want to test.
+		$this->importer = new \ConvertKit_Admin_Importer_ConvertKit_Legacy_Forms();
+
+		// Confirm initialization didn't result in an error.
+		$this->assertNotInstanceOf(\WP_Error::class, $this->importer);
+
+		// Define the blocks to test.
+		$content = '<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . '"} /-->' . $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 ), $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'], $_ENV['CONVERTKIT_API_FORM_ID'] )
+		);
+	}
+
+	/**
+	 * Test that get_form_ids_from_content() returns Kit legacy form block Form IDs
+	 * (in addition to shortcode Form IDs), ignoring any non-legacy Kit form blocks.
+	 *
+	 * Exercises the block-extraction extension to the get_form_ids_from_content()
+	 * override on the Kit Legacy Forms importer.
+	 *
+	 * @since   3.3.5
+	 */
+	public function testGetKitLegacyFormsFormIDsFromContentForBlocks()
+	{
+		// Initialize the class we want to test.
+		$this->importer = new \ConvertKit_Admin_Importer_ConvertKit_Legacy_Forms();
+
+		// Confirm initialization didn't result in an error.
+		$this->assertNotInstanceOf(\WP_Error::class, $this->importer);
+
+		// Define content containing both legacy and non-legacy Kit form blocks,
+		// plus a legacy shortcode, to confirm both block and shortcode IDs are
+		// surfaced when they reference a legacy form.
+		$content = '<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . '"} /-->'
+			. '<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"} /-->'
+			. '[convertkit_form form="' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . '"]';
+
+		// Extract form IDs from content.
+		$form_ids = $this->importer->get_form_ids_from_content( $content );
+
+		// Assert only the legacy form ID is returned (deduplicated across the
+		// shortcode and block references).
+		$this->assertCount( 1, $form_ids );
+		$this->assertEquals( (string) $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'], $form_ids[0] );
+	}
+
+	/**
+	 * Test that get_forms_in_posts() only returns post IDs whose content
+	 * contains a Kit Form shortcode or block referencing a legacy form ID.
+	 *
+	 * Exercises the get_forms_in_posts() override on the Kit Legacy Forms
+	 * importer, which narrows the parent class's broad SQL match.
+	 *
+	 * @since   3.3.5
+	 */
+	public function testGetKitLegacyFormsInPosts()
+	{
+		// Initialize the class we want to test.
+		$this->importer = new \ConvertKit_Admin_Importer_ConvertKit_Legacy_Forms();
+
+		// Confirm initialization didn't result in an error.
+		$this->assertNotInstanceOf(\WP_Error::class, $this->importer);
+
+		// Create a post containing a non-legacy Kit Form shortcode.
+		$nonLegacyShortcodePostID = $this->factory->post->create(
+			[
+				'post_type'    => 'page',
+				'post_status'  => 'publish',
+				'post_title'   => 'Kit Legacy Forms: Non-Legacy Shortcode Post',
+				'post_content' => '[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+			]
+		);
+
+		// Create a post containing a non-legacy Kit Form block.
+		$nonLegacyBlockPostID = $this->factory->post->create(
+			[
+				'post_type'    => 'page',
+				'post_status'  => 'publish',
+				'post_title'   => 'Kit Legacy Forms: Non-Legacy Block Post',
+				'post_content' => '<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"} /-->',
+			]
+		);
+
+		// Create a post containing a legacy Kit Form shortcode.
+		$legacyShortcodePostID = $this->factory->post->create(
+			[
+				'post_type'    => 'page',
+				'post_status'  => 'publish',
+				'post_title'   => 'Kit Legacy Forms: Legacy Shortcode Post',
+				'post_content' => '[convertkit_form form="' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . '"]',
+			]
+		);
+
+		// Create a post containing a legacy Kit Form block.
+		$legacyBlockPostID = $this->factory->post->create(
+			[
+				'post_type'    => 'page',
+				'post_status'  => 'publish',
+				'post_title'   => 'Kit Legacy Forms: Legacy Block Post',
+				'post_content' => '<!-- wp:convertkit/form {"form":"' . $_ENV['CONVERTKIT_API_LEGACY_FORM_ID'] . '"} /-->',
+			]
+		);
+
+		// Fetch the list of post IDs that contain a legacy Kit form reference.
+		$post_ids = $this->importer->get_forms_in_posts();
+
+		// Cast post IDs to ints for comparison (wpdb returns strings).
+		$post_ids = array_map( 'intval', $post_ids );
+
+		// Assert only the legacy posts are returned, and the non-legacy posts are not.
+		$this->assertContains( $legacyShortcodePostID, $post_ids );
+		$this->assertContains( $legacyBlockPostID, $post_ids );
+		$this->assertNotContains( $nonLegacyShortcodePostID, $post_ids );
+		$this->assertNotContains( $nonLegacyBlockPostID, $post_ids );
+	}
+
 	/**
 	 * Test that the get_form_ids_from_content() method returns MC4WP form shortcode Form IDs
 	 * ignoring any other shortcodes.
@@ -539,21 +921,21 @@ public function testMC4WPReplaceShortcodesInContent()
 		// Test each shortcode is replaced with the Kit form shortcode.
 		foreach ( $shortcodes as $shortcode ) {
 			$this->assertEquals(
-				'[convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 				$this->importer->replace_shortcodes_in_content( $shortcode, 10, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 
 			// Prepend and append some content.
 			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode.';
 			$this->assertEquals(
-				'Some content before the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode.',
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode.',
 				$this->importer->replace_shortcodes_in_content( $content, 10, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 
 			// Prepend and append some content and duplicate the shortcode.
 			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode: ' . $shortcode;
 			$this->assertEquals(
-				'Some content before the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 				$this->importer->replace_shortcodes_in_content( $content, 10, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 		}
@@ -574,7 +956,7 @@ public function testMC4WPReplaceShortcodesInContentIgnoringOtherShortcodes()
 
 		// Define the shortcodes to test.
 		$shortcodes = [
-			'[convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+			'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 			'[a_random_shortcode]',
 		];
 
@@ -693,21 +1075,21 @@ public function testMailPoetReplaceShortcodesInContent()
 		// Test each shortcode is replaced with the Kit form shortcode.
 		foreach ( $shortcodes as $shortcode ) {
 			$this->assertEquals(
-				'[convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 				$this->importer->replace_shortcodes_in_content( $shortcode, 10, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 
 			// Prepend and append some content.
 			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode.';
 			$this->assertEquals(
-				'Some content before the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode.',
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode.',
 				$this->importer->replace_shortcodes_in_content( $content, 10, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 
 			// Prepend and append some content and duplicate the shortcode.
 			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode: ' . $shortcode;
 			$this->assertEquals(
-				'Some content before the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 				$this->importer->replace_shortcodes_in_content( $content, 10, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 		}
@@ -728,7 +1110,7 @@ public function testMailPoetReplaceShortcodesInContentIgnoringOtherShortcodes()
 
 		// Define the shortcodes to test.
 		$shortcodes = [
-			'[convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+			'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 			'[a_random_shortcode]',
 		];
 
@@ -846,21 +1228,21 @@ public function testNewsletterReplaceShortcodesInContent()
 		// Test each shortcode is replaced with the Kit form shortcode.
 		foreach ( $shortcodes as $shortcode ) {
 			$this->assertEquals(
-				'[convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 				$this->importer->replace_shortcodes_in_content( $shortcode, 0, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 
 			// Prepend and append some content.
 			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode.';
 			$this->assertEquals(
-				'Some content before the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode.',
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode.',
 				$this->importer->replace_shortcodes_in_content( $content, 0, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 
 			// Prepend and append some content and duplicate the shortcode.
 			$content = 'Some content before the shortcode: ' . $shortcode . ' Some content after the shortcode: ' . $shortcode;
 			$this->assertEquals(
-				'Some content before the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode: [convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+				'Some content before the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"] Some content after the shortcode: [convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 				$this->importer->replace_shortcodes_in_content( $content, 0, $_ENV['CONVERTKIT_API_FORM_ID'] )
 			);
 		}
@@ -881,7 +1263,7 @@ public function testNewsletterReplaceShortcodesInContentIgnoringOtherShortcodes(
 
 		// Define the shortcodes to test.
 		$shortcodes = [
-			'[convertkit_form id="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
+			'[convertkit_form form="' . $_ENV['CONVERTKIT_API_FORM_ID'] . '"]',
 			'[a_random_shortcode]',
 		];
 
diff --git a/views/backend/settings/tools.php b/views/backend/settings/tools.php
index 728fe380a..315fa3ada 100644
--- a/views/backend/settings/tools.php
+++ b/views/backend/settings/tools.php
@@ -118,11 +118,15 @@
 
 			<p class="description">
 				<?php
-				printf(
-					/* translators: %s: Importer title */
-					esc_html__( 'Automatically replace %s form shortcodes and blocks with Kit form shortcodes and blocks.', 'convertkit' ),
-					esc_html( $importer['title'] )
-				);
+				if ( ! empty( $importer['description'] ) ) {
+					echo esc_html( $importer['description'] );
+				} else {
+					printf(
+						/* translators: %s: Importer title */
+						esc_html__( 'Automatically replace %s form shortcodes and blocks with Kit form shortcodes and blocks.', 'convertkit' ),
+						esc_html( $importer['title'] )
+					);
+				}
 				?>
 				<br />
 			</p>
diff --git a/wp-convertkit.php b/wp-convertkit.php
index 4b8eb1acc..c2afddcf5 100644
--- a/wp-convertkit.php
+++ b/wp-convertkit.php
@@ -121,6 +121,7 @@
 require_once CONVERTKIT_PLUGIN_PATH . '/admin/importers/class-convertkit-admin-importer-activecampaign.php';
 require_once CONVERTKIT_PLUGIN_PATH . '/admin/importers/class-convertkit-admin-importer-aweber.php';
 require_once CONVERTKIT_PLUGIN_PATH . '/admin/importers/class-convertkit-admin-importer-campaignmonitor.php';
+require_once CONVERTKIT_PLUGIN_PATH . '/admin/importers/class-convertkit-admin-importer-convertkit-legacy-forms.php';
 require_once CONVERTKIT_PLUGIN_PATH . '/admin/importers/class-convertkit-admin-importer-mc4wp.php';
 require_once CONVERTKIT_PLUGIN_PATH . '/admin/importers/class-convertkit-admin-importer-mailpoet.php';
 require_once CONVERTKIT_PLUGIN_PATH . '/admin/importers/class-convertkit-admin-importer-newsletter.php';