Beginning with FreeBSD 6.2-RELEASE, binary 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 or SMP kernels distributed as a part of an official FreeBSD release. The freebsd-update(8) utility requires that the host being upgraded have 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.