Hey for now you have to update your device MIUI 9.5 as  MiUi 10 have started rolling out to supported devices in closed beta testing only , currently that is available for Redmi Note 5 Pro and Mi MIX 2 devices and Mi 5 in India, more devices will be receiving in sometime.However currently there is no appropriate schedule for stable MiUi 10 ROM, please stay tuned to Mi Community for official announcements/information on updates