The new feature is compatible with Windows PCs, and is only available in the the Indian market for now. The software also incorporates a Mi Fit app update. It allows the Bands to sign in using Apple ID credentials for the first time. The update also comes with applicable bug-fixes for the 2 devices.
They are the same resources with v86 from firmware v1.0.7.74!
Comparing the file of v1.0.9.53 to v1.0.9.42 (latest stable), it seems that some NFC code has been added, but no PAI code included yet (which was included in v1.0.7.74).