syspatch helps provide binary patches to OpenBSD.
$ doas syspatch
System patching can be automated by setting up a cronjob:
$ doas crontab -e
At the bottom, add this line:
0 * * * * sleep $((RANDOM % 43200)) && /usr/sbin/syspatch
A random sleep has been added to ensure that the update starts at a unique time. This prevents all machines from running the exact same job at the exact same time, which would slow down the system.