How to determine tableau server version

Question

I've been looking for this for the better part of a day. Could someone possibly explain me how to access the Tableau server version?

Folder/file references are only valid up to the first decimal place, for example, 8.1. That isn't precise enough. I couldn't find it either in the admin portal or the user portal.

I'm looking for the precise version, which is 8.1.6.

Thanks