](https://wiki.archlinux.org/index.php?title=Dm-crypt/Device_encryption&oldid=824010#Encrypt_an_e…
https://bugs.launchpad.net/ubuntu/+source/cryptsetup/+bug/2014228/comments/5 seems to recommend instead cryptsetup reencrypt.
The Ask Ubuntu question 1445879 faces the same issue as me.
DuckDuckGo and Google search "cryptosetup-reencrypt".
Let us figure out why I faced above in https://gitea.lemnoslife.com/attachments/f3fda48c-04fc-4a5c-ac80-d884d6cde31c:
I recommend switching to cryptsetup-reencrypt, which is properly maintained and tested upstream even when the format of the LUKS header changes (to my knowledge, this has at least happened twice…
The Ask Ubuntu answer 369623 states quickly that it is not possible.
https://forums.linuxmint.com/viewtopic.php?t=391261 seems more about not identical backup and restore.