syspatch helps provide binary patches to OpenBSD. Simply run:
$ doas syspatch
This process can be automated by setting up a cronjob:
$ doas crontab -e
0 * * * * sleep $((RANDOM % 43200)) && /usr/sbin/syspatch
Notice that a random sleep has been inserted to ensure that the update starts at a unique time. This is designed to prevent all machines from running the exact same job at the exact same time, which would cause performance issues.