This update has been hitting both T-Mobile S6 and S6 edge since this morning. For people that haven't updated to 5.1.1 and were on 5.0.2 is of 635MB for the rest who updated last month to 5.1.1 is about 128MB or something like that.
No major changes or even a new feature (For people already on 5.1.1) but some are saying that the Memory leak has been fixed or at least it's better and some other say that is to fix the Wifi calling and VoLTE drain bug, anyways, if it is to fixed any of the above, it will be greatly welcome from everybody.