Is it possible to upgrade the warcamp in this current version? I'm at the point where I'm stuck on the Elixir of Life quest, which I assume is normal, but I tried to gather enough supplies to upgrade the camp in the meantime. I got 30 supply parcels which is what Worm requested but it seems I cannot upgrade it. Does it only work after you get the Sappers?

It can only be upgraded once at this point, so yes if you need to collect boxes of supplies and no if the bomb squad and others.