[MI9] Upgrade process


May 6, 2021
Hi, I've been using xiaomi.eu rom for quite some time without updating. Currently I'm on version 9.7.4 (MIUI 10).

What does the process look like if I wanted to upgrade to stable 12.5 MIUI version? Do I have to wipe /data, update TWRP or something else before flashing ROM?
And in case I don't like the new system or something doesn't work, can I safely downgrade back to what I have now using TWRP backup?