How to perform OpenBSD System Upgrades?

For decades the OpenBSD team reliably publishes upgrade guides such as this one “Upgrade Guide: 6.9 to 7.0”. The easiest way to upgrade machines is the unattended upgrade:

doas su
sysupgrade

The program will download all install the sets, verify their signatures, and reboot to perform the upgrade automatically.

In some cases, configuration files cannot be modified automatically. After reboot, run

doas su
sysmerge

Which will likely bring up ssh, which we can usually ignore.

===> Displaying differences between ./etc/ssh/sshd_config and installed version:

--- /etc/ssh/sshd_config        Thu Jul  1 07:13:37 2021
+++ ./etc/ssh/sshd_config       Thu Sep 30 20:00:43 2021

Next delete old files listed in the guide and finish by upgrading the packages using

pkg_add -u

It’s this easy.