We are working on complex mobile game and we almost ready to release. We have some critical IL2CPP issues on 5.1.3p3 that were fixed in 5.2. But UGUI in 5.2.x version is working too slow than 5.1.3 on mobile devices (iPad mini 3rd gen, iPad 4, etc.). Lags are very noticeable in scrollview – in Unity 5.1.3 dragging of scroll content is very smooth, but on Unity 5.2.x (including last patch 5.2.1p1) it’s very dirty and laggy.
So we can’t release game on 5.1.3 due to IL2CPP crashes, but we also can’t bear these UI lags on very popular devices.
The main question - for what reason this may happen? I didn’t found bug in a public bug tracker.