Every few weeks I meet a system I set up with full disk encryption on luks1, sendiri cari pasal, upgrade it to luks2, then :akasad: when the system doesn't boot.
In an hour of troubleshooting where I get to the verge of reinstalling the system but still myself because that's ludicrously inefficient, I remember luks2 doesn't work with grub and revert all my upgrades. System then merrily boots.
This has happened twice.
I expect my brain to forget about this again in a few weeks so this time I'm reminding myself by writing it down.