ftp_mdtm gets the last modified time for a remote file.
Not all servers support this feature!
ftp_mdtm does not work with directories.
An FTP\Connection instance.
The file from which to extract the last modification time.
Returns the last modified time as a local Unix timestamp on success, or -1 on error.
|8.1.0||The ftp parameter expects an FTP\Connection instance now; previously, a resource was expected.|