The Megapov variant appeared before the 3.5 POV-Ray. At this moment, it was merely a collection of patches coming along with a respectable number of new features.
When the 3.5 POV-Ray was released, the POV-Team only kept a few of the famous 0.7 Megapov features, and made some changes in the script language, endangering the Megapov edition because of its loss of compatibility with the standard.
But instead of disapearing because of the evolution of POV-Ray, the coders rebuilt a brand new 1.0 Megapov version based on POV-Ray 3.5. Of course, they kept the features that didn't make into POV-Ray 3.5, released a new set of patches and made sure that the old script language of 0.7 could still be read in 1.0.
The main features compared to POV-Ray 3.5 are :
Anyway, it seems that if we can't expect a new POV-Ray version before long, it certainly shouldn't be the same with Megapov. We can suppose that Megapov 1.x will have a very fast development just like the previous versions which showed a lot of new features and optimizations in a very short spawn.