A week ago the power supply of our server died and it took part of of the hard disk with it. Jaap did an amazing job -- he bought the new server and using a USB stick with the OpenBSD installation media he set up the new server, including partitions and filesystems.

So now we're on OpenBSD 5.8. In the process I switched to Apache 2.4.16 (instead of the custom build of the old Apache 1.x that OpenBSD used to maintain), and from MySQL to MariaDB. The site is now back up and running, with some minor tweaks to be done. The pink error messages will go away.

# uname -a
OpenBSD zolder.fritz.box 5.8 GENERIC.MP#1236 amd64