Mi Pay is a service similar to Apple Pay, used to pay by our phone by using NFC after integration of payment card with smartphone. Xiaomi has just released an update for Xiaomi Mi6 which launches this service for Mi6’s owners and improves some functions of system.
Update has 126MB and updates MIUI to 8.2.26.0 version of the system. So far, Mi Pay service works only in China, and it can be used by customers of China's largest banks such as China Construction Bank or China Merchants Bank. We don't know when this service will be available in other countries.