Upgrade from 3.40OE

I am currently running custom 3.40oe but was told some newer games need higher custom firmware. I am not sure which I should go to next. Any help would be appreciated.

Do you have any games that require you to upgrade, or some games you might get?
3.52 M33-4 allows for great customization and no bugs. I've used it for quite a while and its great.
Or 3.71 M33-4 would be a good choice.