More than likely the ongoing problems with payment processors and making the switch to the other alternatives which probably involve some talks or paper work(opening new accounts and cards etc) on top of updating the games and whatever real world stuff they got going on
So, apparently the problems with Dlsite have already been solved, but Milk Engine said he is moving to another apartment, so Sana will be delayed again until some unspecified point in November, although he plan to release a trial version soon.