private function createZipBackup() {
		if (class_exists ( \ZipArchive::class )) {
			$zip = new \ZipArchive ();
			$file_name = $this->file_name . '.zip';
			if ($zip->open ( $file_name, \ZipArchive::CREATE ) === TRUE) {
				$zip->addFile ( $this->file_name, basename ( $this->file_name ) );
				$zip->close ();
				
				@unlink ( $this->file_name );
				$this->file_name = $file_name;
			}
		} else {
			echo "ZipArchive missing class ";
		}
	}