As far as supporting Windows users, WinOF4.8 is the last official version that supported ConnectX2 cards. As Mellanox releases new drivers, those are also including features that have strong dependency with FW releases and MS OS releases.
Unfortunately, it became almost impossible for ConnectX2 cards to catch up with the new feature and capabilities and therefore the driver releases had to continue without it.
specifically, i know of few folks that are using WinOF 4.9 and ConnectX2 cards and it works. It was not tested and released this way - still, it doesn't stop people from trying ;-)
Cheers!