So i tried to update to the newest developer Beta version and it just gives me the error:
you're allowed to flash the newest develop version published by miui forum from stable version only.

Download an older version of Beta, say, 9.4.26 and try again. You can find the ROM thread in my profile. Download the Recovery ROM and flash it. Make sure the download is not paused or interrupted in between - it might corrupt the file giving you errors. Once you are on Beta channel, you can update to latest version through OTA. Don't forget to MAKE A BACKUP since switching ROMs will wipe all data.

Cheers! :-)