We will be offering the EFI V2 with support for Kepler in addition to DP 1.3 and 1.4 for Pascal and Maxwell. So 4K boot screens for a GT630/40 as well as GTX680 and GTX780.
I'dsay no more than 2 weeks. So if considering a 630/640 for Mojave, might be better to hold off. There will be a small price increase to cover R & D for new EFI. If you don't need 4K boot screens now or ever, buy the older version at regular price.
These new EFIs will be released in stages, starting with GTX1070Ti.