Xiaomi today launched MIUI 9 with Redmi Y1 and Redmi Y1 lite. Here is a list of MIUI9 features.
Revamped notifications center
Swap split screen
Smart photo editing
MIUI9 also have some India only features which includes smart IRCTC card, Panchang calendar,holidays,festivals, scores builtin to their own Calendar app and stickers.
Just like Google Now, Oneplus Shelf, now Xiaomi have App Vault which can access by swiping right from the home screen.
As per Xiaomi, MIUI 9 will also fix the KRACK WPA vulnerability with a security patch which will be sent to most of the Xiaomi phones.
Also read: List of MIUI9 compatible Devices