Xiaomi updates the smartphones that sell much more than others. Mi5/PRO sold much more than Mi5S so the resources of development are dedicated to this phone and newers..so our is sometimes forgotten or updates will arrivare later
On mi5s, with dalvik and cache cleaned after installation, I've sometimes problems with Bluetooth in my car (Audi A1). The Bluetooth connect and disconnect every 5 minutes
I noticed 2 problems:
1) in Chrome when I try so copy the URL, the app resize from top and remains smaller after the copy action
2) in the calendar "birthday of", I've it in Italian language, is shown in Dutch
Is part of the rom. Newest operative system are rom parts don't worry :) an OS are so many files runned so update directly and if you want you can do a factory reset to enjoy the new OS