If you use WordPress 4.4 and you failed to update themes and plugins you have to follow these steps:
Login to your ftp and go wp-admin ->> includes and edit class-wp-filesystem-ftpext.php
$file_list = @ftp_nlist( $this->link, ‘-a ‘ . $path );
$file_list = @ftp_nlist( $this->link, $path );
Now you will be able to update again wordpress plugins and themes with no problem!