Which is the more advanced, tougher to crack encryption mode? I assume GCM is better because it is newer isn't it? I read some forums where people were talking about it a little but I couldn't find a straight answer to my question.
GCM ist newer, faster and more reliable than CBC.
More and more companies are switching to GCM.
Also with OpenVPN 2.4 GCM is preffered by server-default.
If you take a look at the .ovpn files, there is an "ignore server default" command
followed by the personal choosen cipher (for example)
If this option "ncp-disable" is removed, the 256-GCM is always used, independent from the configurated or choosen chipher (overriding)...because it is the preffered default chipher.
You should choose the 256 or 128-GCM profiles at the Download area