It’s a dot .
Vista 3 is a version. Vista 4 is a version.
Then, in Vista 4 comes a dot. So, you get Vista 4.x
The .x is an application pack (by this vendor’s definition). So Vista 4.1 is Version 4, Application Pack 1.
And Vista 4.1.2 is Version 4, Application Pack 1, Service Pack 2.
Vista 4.2 is Version 4, Applicaton Pack 2.
I think this is supposed to be user friendly. I found it confusing at first but I guess I’m catching on.
Would you like to voice a friendlier way to version one’s product?