Hi,
The official documentation on https://www.spacemacs.org/doc/DOCUMENTATION.html recommends to update Spacemacs via the old
internal fixed-release update mechanism. Only here on github on the Readme.md it's noted that Spacemacs entirely switched to rolling release with the develop branch.
I found those contradictory informations very confusing and it took me some time to figure out which one was right, since both are the "official" docs. Please fix