We're in the middle of a physics rewrite that's taken longer that we had hoped ...
Once Alpha 15 is out, I hope you'll think it was worth the wait.
To elaborate; the physics library have been growing organically for a long time. This and that was being added on top, and it worked ok. While collisions were rewritten, to deal with large issues, physics just grew layer by layer, with only little design changes now and then.
In the end, it had grown to a point where its core design and the current use didn't match very well, and something had to be done.... or rather... something didn't _have_ to be done, but it would make the most sense in the long run.
Some in here have argued that we should more or less lock down features and any larger refactoring, and only focus on fixing bugs. It would seem that "alpha version" is a confusing term then, since the alpha development phase is really for doing what we are doing. Trying out things, discovering issues with that and trying to do it differently and better _and_ fixing bugs, naturally.
Alpha versions have historically been for in-house use only, but lately there is a trend towards involving the community more, and letting it have a voice in deciding what works and what doesn't, and this is what we have been doing. That doesn't mean that an alpha version should then be considered a beta version with a different name.
To those who get bored and irritated from waiting, because there is not always a new version every 1st of the month, even though we will try hard to make that happen, please consider that the alternative would really be that there was no new versions at all before a beta is ready.
As Dan has pointed out, a faster release cycle is a priority, but right here and now, it is prevented because I essentially pulled the engine out and have it lying on the floor in parts. New gears have been manufactured, oil has been refilled and the parts are going in again as quickly as my little fingers can manage.... soon...
anyway. its all my fault, so feel free to blame me. I hope you will later see that it was worth it.... to rewrite.. not to blame ;-)