Can i install a rom over another?

[desirablenickname]

i'm kinda new to stuff like this so this is probably a dumb question but I have installed miui 11 stable rom on my mi 9 lite, can i just install miui 12 rom over it? or do i need to wipe everything and do the whole procedure as the first time?

 

[ridzalm]

If you are currently running xiaomi.eu MIUI 11 stable, you can dirty flash to xiaomi.eu MIUI 12 stable and you won't have to perform a wipe. But do expect some bugs, if there are any.

I myself did a dirty flash from MIUI 11 weekly to MIUI 12 weekly. Make sure you have a NANDROID backup prior to flashing and transfer the backup file to your desktop PC/laptop.