In a different codebase, I've upgraded TurboGears & WebOb recently, so I'm going to apply those learnings to Allura. My target is TurboGears 2.3.2 and WebOb 1.3.1. Further upgrades need to be done, but can be separate to make the changes less overwhelming then they already are going to be.
Resources:
allura,forgepastebin,forgehg:db/8273
Merged.