Sí están usando Boeffla, changelog sacado de aquí
http://en.miui.com/thread-108331-1-1.html
Changelog 6.3.17:
CMCC China Mobile Display repair problems
Optimize the use of the kernel Boeffla
Optimization of the last two weeks following the official updates
Additional optimization settings, click on continuous open kernel tuning (Shen Ru)
Thanks Boeffla kernel author, Thanks