Qubes-dist-upgrade (4.0 to 4.1) Break down / Manual upgrade option

Is it possible to get a detailed user friendly explanation / break down of the steps (Stages 0 to 6) that the qubes-dist-upgrade script performs with a view to being able to manually negotiate stages were the script fails, and know / understanding all the things that need to change from a working qubes 4.0 system to a working qubes 4.1 system?

This is obviously technical and not for everybody but I think it could have benefits, for debugging the script and assisting people to get upgraded by the 4th of August when Qubes-OS 4.0 become obsolete.

It could also answer questions like:

  • Has the qubes-os file system changed (from 4.0 to 4.1)?
  • Can I still boot the old qubes 4.0 kernel? … before I have completed the distribution upgrade process? … after the distribution upgrade is complete?
  • Will a qube (VM) upgrade (STAGE2 /home/user/QubesIncoming/dom0/upgrade-template-standalone.sh) prevent a qube (VM) running in the old qubes-os 4.0 kernel / Xen-hypervisor?
  • Can I upgrade a qube (VM) after I have upgraded and booted Qube-OS 4.1 or do I have to do the qube (VM) upgrade in Qube-OS 4.0 (before I boot into the 4.1 system)?
  • Can some steps be skipped / postponed until after the upgrade? (For examples STAGE 1 and STAGE 2 – >> see Wrong but still successful manual upgrade to 4.1)

Here is the script for Stage 2: https://github.com/QubesOS/qubes-dist-upgrade/blob/release4.0/scripts/upgrade-template-standalone.sh