diff --git a/src/wp-admin/includes/class-wp-upgrader.php b/src/wp-admin/includes/class-wp-upgrader.php
index 88c6d5d604..c1d65972c8 100644
--- a/src/wp-admin/includes/class-wp-upgrader.php
+++ b/src/wp-admin/includes/class-wp-upgrader.php
@@ -594,35 +594,17 @@ class WP_Upgrader {
 		}
 
 		// Copy new version of item into place.
-		if ( class_exists( 'Rollback_Update_Failure\WP_Upgrader' )
-			&& function_exists( '\Rollback_Update_Failure\move_dir' )
-		) {
-			/*
-			 * If the {@link https://wordpress.org/plugins/rollback-update-failure/ Rollback Update Failure}
-			 * feature plugin is installed, use the move_dir() function from there for better performance.
-			 * Instead of copying a directory from one location to another, it uses the rename() PHP function
-			 * to speed up the process. If the renaming failed, it falls back to copy_dir().
-			 *
-			 * This condition aims to facilitate broader testing of the Rollbacks (temp backups) feature project.
-			 * It is temporary, until the plugin is merged into core.
-			 */
-			$result = \Rollback_Update_Failure\move_dir( $source, $remote_destination );
-		} else {
-			$result = copy_dir( $source, $remote_destination );
-		}
-
-		if ( is_wp_error( $result ) ) {
-			if ( $args['clear_working'] ) {
-				$wp_filesystem->delete( $remote_source, true );
-			}
-			return $result;
-		}
+		$result = copy_dir( $source, $remote_destination );
 
 		// Clear the working folder?
 		if ( $args['clear_working'] ) {
 			$wp_filesystem->delete( $remote_source, true );
 		}
 
+		if ( is_wp_error( $result ) ) {
+			return $result;
+		}
+
 		$destination_name = basename( str_replace( $local_destination, '', $destination ) );
 		if ( '.' === $destination_name ) {
 			$destination_name = '';