I'm using the dev version of the multi-languge MIUI v.6 (5.1.23) on MI3 (englesh language). Sms / e-mail notifications do work just fine... It is only the incoming call feature that does not work... I'm in stead met with the normal call pop-up/change of screen. I have seen multiple sites and youtube videos where incoming calls behave just like the floating notification for sms.