Lifehack how to find out the Revit version of a file. Of course you can update the project to the latest version, but this may cause problems for others in the team.

So instead of opening an old project and trying to guess what version it is. You can open the file with: Notepad

Ctrl+F search the file and search for: B u i l d

Be sure to have spaces between the letters. The Revit version will be next to it.