Where did you hear about v3.1?

Regarding the original TN1 Grindhouse, I am only aware of three releases:

(1) 1080p mkv, non-Bluray compatible and with some video glitches near the end.
(2) 1080p ISO, Bluray compatible, with no glitches. This supersedes (1), is widely available, and fits on a BD25 for playback on a standalone Bluray player.
(3) 720p mkv which has “DVD9” in the filename but is a tad too big to fit on such a disc…

There was a “version 2” of the Grindhouse which was based on a totally different print, and is known as the “DCP 2013”. This is in 1080p and bizarrely in wmv format, has more vibrant colours than the main Grindhouse, but to my eyes is less sharp. It took me a while to track down and seems only to be available on Usenet as far as I know.

More recently, Dreamaster released a single pass colour-corrected version of the original Grindhouse. This is in mkv format and in 1080p.

Bluto