How to upgrade FreeBSD 15.0 to 15.1 with freebsd-update

FreeBSD 15.0 reaches end of life on 30 September 2026. If you are still running it, now is the time to move to 15.1. In the accompanying video, I take a fresh 15.0 installation through the upgrade and show each stage as it happens.

Watch the full video:

This guide covers systems installed using the traditional distribution sets and updated with freebsd-update. FreeBSD 15 also supports a packaged base system, which has a different upgrade process. You can check which type you have with:

pkg which /usr/bin/uname

If it says /usr/bin/uname was not found in the database, this is the method for you. If it returns a FreeBSD-runtime package, use the pkgbase instructions instead.

Before starting on a live system, make sure you have a working backup, read the 15.1 release notes and errata, and allow time for the reboots. I use doas in the video. If you use sudo, substitute that, or run the commands as root.

Bring 15.0 up to date first

Check the version you are running:

freebsd-version -kru

I prefer to apply the available patches for the current release before moving to the next one:

doas freebsd-update fetch
doas freebsd-update install

When fetch says it is applying patches, it is preparing the update in its working directory. It is not yet replacing the files on the running system. That happens when you run install.

Read the list of files to be added, changed or removed before accepting it. Most of the time there is nothing surprising, but it is worth checking on a machine with its own configuration and services.

If the patch updates the kernel, reboot and check that no further patches are waiting:

doas reboot
doas freebsd-update fetch

I also update the installed packages before beginning the release upgrade:

doas pkg update
doas pkg upgrade

Upgrade to 15.1

Fetch and prepare the new release:

doas freebsd-update upgrade -r 15.1-RELEASE

This stage can take a while. Check the components it identifies and review any proposed configuration merges and file changes. Once it has finished preparing the upgrade, install the new kernel:

doas freebsd-update install
doas reboot

After the machine comes back, run install again. This stage installs the rest of the base system:

doas freebsd-update install

Follow any instructions it prints about third-party software. In the video I run pkg update and pkg upgrade at this point. The example machine is a fresh installation, so it has no packages to replace, but an established server may have more work to do:

doas pkg update
doas pkg upgrade

Then run install once more to remove the old base-system files:

doas freebsd-update install

Do not skip that last command. The upgrade is not finished just because the system has rebooted into the 15.1 kernel.

Boot environments and the final checks

On my ZFS installation, freebsd-update install creates a boot environment before making changes. That gives me a way back through the boot menu if an upgrade goes wrong. Check that this is actually happening on your system: it depends on having a suitable ZFS root and the CreateBootEnv setting. It does not replace a separate backup.

The FreeBSD 15.1 upgrade instructions also include a boot-loader step. Check whether your machine uses UEFI or BIOS with sysctl machdep.bootmethod, then follow the instructions for that layout. The commands depend on your disks and boot setup, so do not copy another machine's device names.

After the final reboot, confirm the installed version and check for remaining updates:

freebsd-version -kru
doas freebsd-update fetch

The machine in the video finished on 15.1-RELEASE-p3, with no further updates available. The exact patch level you see will depend on when you run the upgrade.

This is the distribution-set method. I will cover upgrading a FreeBSD system installed with pkgbase separately.