Put new twrp version inside internal storage.
Boot your device into Twrp recovery and choose the Install option
At the bottom corner, you should “Install Image” and select it.
Navigate to the New TWRP image file and then select Recovery.
Swipe to flash and reboot your system, that’s it.
Both, via updater takes more time to show up, via twrp is more faster, download and put inside internal storage.
Trwp Install - Rom - Wike Dalvik Cache - Reboot system
If u have problems check my post - https://xiaomi.eu/community/threads/last-8-11-15.47670/post-461006
You need update Twrp 3.2.3 Tremble - https://drive.google.com/file/d/1xggD0fntmpniyIrjPfizE4D6D2AdwJJX/view
This version is the only one who supports Oreo rom's.
And after that u can install...