With the introduction of Version 3, GTP is a multiuser system.
Multiple users can share a single file, just like a cloud application.
Changes by any user are shared online with all other users.
This also holds true for the readonly access by GTP Reader.
GTP requires a simple file share in your existing IT infrastructure.
Remote access by VPN connections are supported.
Your data is stored on your servers. All your Security systems are in place.
Of course you can still use GTP as a single place system with a local file.