diff --git a/wp-admin/includes/meta-boxes.php b/wp-admin/includes/meta-boxes.php
index 805d69cac7..508168a5bf 100644
--- a/wp-admin/includes/meta-boxes.php
+++ b/wp-admin/includes/meta-boxes.php
@@ -1463,21 +1463,18 @@ function register_and_do_post_meta_boxes( $post ) {
 	}
 
 	if ( post_type_supports( $post_type, 'custom-fields' ) ) {
-		$screen = get_current_screen();
-		if ( ! $screen || ! $screen->is_block_editor() || (bool) get_user_meta( get_current_user_id(), 'enable_custom_fields', true ) ) {
-			add_meta_box(
-				'postcustom',
-				__( 'Custom Fields' ),
-				'post_custom_meta_box',
-				null,
-				'normal',
-				'core',
-				array(
-					'__back_compat_meta_box'             => false,
-					'__block_editor_compatible_meta_box' => true,
-				)
-			);
-		}
+		add_meta_box(
+			'postcustom',
+			__( 'Custom Fields' ),
+			'post_custom_meta_box',
+			null,
+			'normal',
+			'core',
+			array(
+				'__back_compat_meta_box'             => ! (bool) get_user_meta( get_current_user_id(), 'enable_custom_fields', true ),
+				'__block_editor_compatible_meta_box' => true,
+			)
+		);
 	}
 
 	/**
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 60b4133159..3c4b39914d 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-beta1-44647';
+$wp_version = '5.1-beta1-44648';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.