Just got installed Grub from Testing:
(1/1) upgrading grub [########################################################################################] 100%
:: To use the new features provided in this GRUB update, it is recommended
to install it to the MBR or UEFI. Due to potential configuration
incompatibilities, it is advised to run both, installation and generation
of configuration:
$ grub-install ...
$ grub-mkconfig -o /boot/grub/grub.cfg
I don’t recall having seen this message before when updating Grub. Good it’s there now to avoid future similar issues as we have seen here lately.