Fixed the issue for PHP 7.2.

FtpFile.php

@@ -11,7 +11,7 @@ namespace gftp;
  * @license GNU LESSER GPL 3
  * @version 1.0
  */
-class FtpFile extends \yii\base\Object {
+class FtpFile extends \yii\base\BaseObject {
 	
 	public $isDir;
 	public $rights;

drivers/FtpDriver.php

@@ -12,7 +12,7 @@ use \Yii;
 /**
  * Basic FTP connection driver.
  */
-class FtpDriver extends \yii\base\Object implements RemoteDriver {
+class FtpDriver extends \yii\base\BaseObject implements RemoteDriver {
 	
 	
 	/**

helpers/Enum.php

@@ -9,7 +9,7 @@ use \ReflectionClass;
  *
  * @author herve
  */
-abstract class Enum extends \yii\base\Object {
+abstract class Enum extends \yii\base\BaseObject {
 	
 	private $name;
 	private $ordinal;