The ota works on .zip ROMs but as we are still using fastboot, you will have to wait until an official TWRP is available. Once it is, the EU Devs will stop fastboot and start .zip ROMs.Hi
I just installed my first ROM yesterday so please take this with a grain of salt lol. The OPs question and your reply reminded me of something I read in the guide before installing my weekly ROM last night.
I thought it said that you would be notified of a new build via the updater app and it would download it for you, but as a fastboot file not a recovery file. Then you transfer that to your computer and then do everything else described
(you can of course just skip the transfer wait time and download from PC to begin with, I'm more just curious if what I read is in fact true and it's just a handy delivery method for the latest fastboot build or if I should never click "update" or "download" if promoted by the system update app)
Usually the ota works from Saturday night ish. Hopefully not too long now.
Of course this is for Xiaomi EU ROMs or other custom ROMs, global, EEA or stock Chinese, the ota works out of the box.