Full improvements list:
Many, many bug fixes in JIT and elsewhere, improving compatibility
Proper fix for Zenfone and related devices
Direct3D 9 supported as a rendering backend on Windows, helps on old GPUs and can be faster than OpenGL in many cases
You can now create specific configs per game
FPU rounding modes much better supported, fixes the Peace Walker boss that was undefeatable. NOTE: This breaks saves in Gods Eater - you must turn off the better rounding, load your save game, turn it on and save.
The JIT now uses SSE on x86, improving speed considerably. This does not affect ARM devices, that's for the next version or two.
Improved audio output code on both Windows and Android, reducing audio latency on Windows and on some Android systems
FFMPEG upgraded, fixed some music hangs ("GHA phase shifts")
Some Ad Hoc improvements, coldbird.net is now default adhoc server. Ad Hoc still unfinished and hard to use.
Graphics fixes: Bezier/spline drawing fixes, vertex position fixes, DanganRonpa on Adreno fixed, flat shading fixed, vertex cache improved, some PowerVR blockiness issues fixed, screen scaling filter added, Google Cardboard support
Simulate UMD speed better, fixing hangs in several games
More Atrac3 fixes, fixing hangs
Somewhat better disk full handling
Fixes to dynamic unloading of code, fixing problems in GEB and TRM 2/3
Updated to SDL2 where applicable (Linux, Mac)
Some new features, like analog/dpad-swap hotkey, graphics hack for Phantasy Star, show last bit of debug log in dev tools, etc
No more need for MSVCRT DLLs on Windows