Instead of using two separate tools, in 15.0 you can opt to deprecate freebsd-update and file sets, and rely entirely on pkg for updating both the base operating system as well as any packages you have installed, because with this new method, the base system moves from file sets to packages. When installing FreeBSD 15.0, the installer will ask you to choose between the old method, or the new pkg-only method.

+ https://next.ink/brief_article/freebsd-15-0-se-modernise-et-permet-les-builds-reproductibles/

+ https://www.ietf.org/archive/id/draft-ietf-acme-dns-persist-00.html