https://linuxiac.com/canonical-plans-controversial-grub-changes-for-ubuntu-26-10-secure-boot/
Canonical wants to remove LUKS disk Encryption, LVM, most mid-raid modes, ZFS, BTRFS and many other file systems and image parsing abilities from GRUB in a recently announced, Planned change to Secure Boot, Supposedly for "security"
In order to retain these features the system would need to not use secure Boot.
Systems that don't use Secure Boot, or rely on the above features, can not upgrade to Ubuntu 26.10
