Four days. Microsoft seem to be improving, I think first submissions of Survivalcraft took longer than that. This version should fix your worlds, and some other minor bugs (e.g. stabbing yourself when throwing down from sneak mode).
The water changes I made for 1.7 so far only affect the water visuals – there are no water physics changes. I wanted to do them as well, but it would take several days, so I decided water is not the most important thing to do at the moment. I am again working on the new animal. I have a brilliant idea for a couple of new blocks to go with it, but will keep it quiet for now, need to see how it works out first to avoid disappointments :-) If it does, I think it will be first class. Will let you know as soon as I have anything to show.
Anyway, have fun with 1.6 while I work on 1.7.