diff --git a/lib/compat/wordpress-6.8/post.php b/lib/compat/wordpress-6.8/post.php
index 2477e94f7393c6..b205e9dc81b894 100644
--- a/lib/compat/wordpress-6.8/post.php
+++ b/lib/compat/wordpress-6.8/post.php
@@ -4,23 +4,16 @@
  * Set the default editor mode for the page post type to `template-locked`.
  *
  * Note: This backports into `create_initial_post_types` in WordPress Core.
- *
- * @param array $args Array of post type arguments.
- * @return array Updated array of post type arguments.
  */
-function gutenberg_update_page_editor_support( $args ) {
-	if ( empty( $args['supports'] ) ) {
-		return $args;
+function gutenberg_update_page_editor_support() {
+	// Avoid enabling the editor for pages when it's not supported.
+	// This is plugin specific safeguard.
+	if ( ! post_type_supports( 'page', 'editor' ) ) {
+		return;
 	}
 
-	$editor_support_key = array_search( 'editor', $args['supports'], true );
-	if ( false !== $editor_support_key ) {
-		unset( $args['supports'][ $editor_support_key ] );
-		$args['supports']['editor'] = array(
-			'default-mode' => 'template-locked',
-		);
+	if ( wp_is_block_theme() ) {
+		add_post_type_support( 'page', 'editor', array( 'default-mode' => 'template-locked' ) );
 	}
-
-	return $args;
 }
-add_action( 'register_page_post_type_args', 'gutenberg_update_page_editor_support' );
+add_action( 'init', 'gutenberg_update_page_editor_support' );