diff --git a/wp-admin/includes/post.php b/wp-admin/includes/post.php
index 999e30a289..31e1a1559e 100644
--- a/wp-admin/includes/post.php
+++ b/wp-admin/includes/post.php
@@ -2245,6 +2245,16 @@ function the_block_editor_meta_boxes() {
 					continue;
 				}
 
+				// If a meta box is just here for back compat, don't show it in the block editor.
+				if ( isset( $meta_box['args']['__back_compat_meta_box'] ) && $meta_box['args']['__back_compat_meta_box'] ) {
+					continue;
+				}
+
+				// If a meta box doesn't work in the block editor, don't show it in the block editor.
+				if ( isset( $meta_box['args']['__block_editor_compatible_meta_box'] ) && ! $meta_box['args']['__block_editor_compatible_meta_box'] ) {
+					continue;
+				}
+
 				$meta_boxes_per_location[ $location ][] = array(
 					'id'    => $meta_box['id'],
 					'title' => $meta_box['title'],
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 2feb4293bf..bfe9146e63 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44221';
+$wp_version = '5.1-alpha-44222';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.