diff --git a/wp-includes/blocks.php b/wp-includes/blocks.php
index 128e38a7e0..f6e023c67f 100644
--- a/wp-includes/blocks.php
+++ b/wp-includes/blocks.php
@@ -207,6 +207,7 @@ function register_block_type_from_metadata( $file_or_folder, $args = array() ) {
 		'supports'        => 'supports',
 		'styles'          => 'styles',
 		'example'         => 'example',
+		'apiVersion'      => 'api_version',
 	);
 
 	foreach ( $property_mappings as $key => $mapped_key ) {
diff --git a/wp-includes/class-wp-block-type.php b/wp-includes/class-wp-block-type.php
index 79b0e3e6d1..7687d2b931 100644
--- a/wp-includes/class-wp-block-type.php
+++ b/wp-includes/class-wp-block-type.php
@@ -16,6 +16,14 @@
  */
 class WP_Block_Type {
 
+	/**
+	 * Block API version.
+	 *
+	 * @since 5.6.0
+	 * @var int
+	 */
+	public $api_version = 1;
+
 	/**
 	 * Block type key.
 	 *
diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-block-types-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-block-types-controller.php
index 5ae139991d..f34ed6ace9 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-block-types-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-block-types-controller.php
@@ -256,6 +256,7 @@ class WP_REST_Block_Types_Controller extends WP_REST_Controller {
 
 		$schema       = $this->get_item_schema();
 		$extra_fields = array(
+			'api_version',
 			'name',
 			'title',
 			'description',
@@ -365,6 +366,13 @@ class WP_REST_Block_Types_Controller extends WP_REST_Controller {
 			'title'      => 'block-type',
 			'type'       => 'object',
 			'properties' => array(
+				'api_version'            => array(
+					'description' => __( 'Version of block API.' ),
+					'type'        => 'integer',
+					'default'     => 1,
+					'context'     => array( 'embed', 'view', 'edit' ),
+					'readonly'    => true,
+				),
 				'title'            => array(
 					'description' => __( 'Title of block type.' ),
 					'type'        => 'string',
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 77257cbf9f..c218862d46 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.6-alpha-49223';
+$wp_version = '5.6-alpha-49224';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.