Upgrades between RELEASE versions (and snapshots of the various security branches) are supported using the freebsd-update(8) utility. The binary upgrade procedure will update unmodified userland utilities, as well as unmodified GENERIC kernel distributed as a part of an official FreeBSD release. The freebsd-update(8) utility requires that the host being upgraded has Internet connectivity.

An older form of binary upgrade is supported through the Upgrade option from the main sysinstall(8) menu on CDROM distribution media. This type of binary upgrade may be useful on non-i386, non-amd64 machines or on systems with no Internet connectivity.

Source-based upgrades (those based on recompiling the FreeBSD base system from source code) from previous versions are supported, according to the instructions in /usr/src/UPDATING.