The question has been closed for the following reason "The question is answered." by DJ Scooby Doo Jul 10 '12 at 00:24
3.x means its the 3rd version and every sub version , the x is a variable, so 3.x means it suports 3.0, 3.1, 3.2, etc, etc,
answered Jul 10 '12 at 00:06
I'm assuming 3.0, like the 3rd revision/version of the software.
answered Jul 09 '12 at 23:53
DJ Scooby Doo