In DOCS I saw it’s better to use newer Kernels.
I should upgrade Kernel only on Host/Qubes-OS or in Whonix-Gateway and Whonix-Workstation too ?
Use the regular update process to receive kernel updates for Qubes dom0 (host) and all templates including Whonix, such as
apt-get update and
Actually the wiki says to “consider” new kernels due to the security benefits baked into later releases as grsec stuff gets mainlined and other ongoing work by Kees Cook and co.
The footnoted caveat is risk of instability/failure to boot etc. So, the user doesn’t have to go out of their way, unless they want to. The benefit might be marginal (?)
Users with specific hardware might also require newer kernels in dom0. Instructions over on Qubes aren’t complicated.