The UPGRADE.txt file step five says "Disable all custom and contributed modules.", how does one know which modules are custom and contributed? Is there any easy/automated way of remembering which modules are enabled so that one can turn on all the right ones again after the upgrade? Or does one just print out the web page and do it manually?
Core are in the "core" section. All others are custom and contributed. Yes, just print out the web page and redo manually.
Good luck. It's usually very easy BTW.