> It is so long ago I last saw a MySQL 8.0 instance that I don't recall > the upgrade details, but in general upgrades from MySQL 5.5, 5.6, 5.7 > and 8.0 start having more divergence, and in-place upgrades no longer > work for 8.4+. I recommend taking a backup, restoring the backup to a > test machine and trying it out before doing it in production.
i performed the migration from debian's mysql 8.0 to mariadb 11.8.8 this evening. it was definitely not handsfree, but it wasn't difficult, either. i suffered about 25 minutes of downtime total, and am no database expert. everything seems to be working fine now.

