I did not ask yet, but there was no need. Nav3 map does not contain Vietnam, it is fact. It is intentional as Vietnam has been under TT radar for two years by now. If it was an error, it must have been discovered. The fact that neither the current nor the earlier Nav3 version of Southeast Asia map does not include Vietnam could only mean one thing: intention.

I don't have suitable smartphone to try GO app, so I'd leave this option for a while.

As regard to what TT says on their website, I am not really interested in making it clear. The usual way the big names go is to tell one thing and sell something different, never admit mistake and always blame customer for not having the latest model. Boring, yeah?