Is it safe to try and install the toaster on FreeBSD 5.21 ?
Mark (yes, the former? openbsd geek)
Believe it or not, I just decided to put this on a dedicated server, so I can reinstall os on it!
FreeBSD 5.x is "safe" but if you are new to FreeBSD, it would be much "safer" to stick with 4.9. You will have issues with 5.x, but if you don't mind doing a little hacking when things go bump, by all means, use 5.1. Just read the FreeBSD docs thoroughly and then you'll be OK.

Matt