Use get_sites() if possible.

Author: lesterchan

uninstall.php

@@ -11,7 +11,7 @@
 
 
 if ( is_multisite() ) {
-	$ms_sites = wp_get_sites();
+	$ms_sites = function_exists( 'get_sites' ) ? get_sites() : wp_get_sites();
 
 	if( 0 < sizeof( $ms_sites ) ) {
 		foreach ( $ms_sites as $ms_site ) {
@@ -43,4 +43,4 @@
  */
 function plugin_uninstalled() {
 	global $wpdb;
-}
+}