Hrm, what is syspatch unhappy about here after the #OpenBSD 6.2 upgrade? That mirror worked for fetching the new base packages.
# uname -mrsv
OpenBSD 6.2 GENERIC.MP#134 amd64
# syspatch
syspatch: invalid URL configured in /etc/installurl
# cat /etc/installurl
https://ftp.fau.de/pub/OpenBSD/
#