This is just a small reminder (mainly for myself) how I did the OpenBSD upgrade and how to keep the packages up-to-date.
The official upgrade instructions is pretty straight forward and self explanatory. Don't let the verbosity scare you away, most of that stuff might not even be relevant to you. I especially appreciate the section that lists everything that is not necessary anymore and can be removed (this goes to the Linux folks out there!).
Another ressource that deemed helpful was the slightly older guide by Peter N. M. Hansteen. In fact the only thing I used (and was looking for for a long time) is the recipe to keep your binary packages up-to-date
to remove unnecessary stuff.