Upgrading discourse is easily done via UI and since several months we never stumbled over an issue although they publish updates frequently. But this time our backups came in handy. So it might be that you need to repeat some questions or answers, I'll also have a look and restore posts manually if I see some missing.
We were fighting with discourse for many hours now but could not fix the issue with the new version
we were having (topics did not open and the request timed out) despite having help from Jeff the founder and others :).
And so we reverted to the previous version v1.6.0.beta1 and imported the backup, while that I investigated also why our backups are so fat but this didn't help and learned a bit more about docker and even a postgres power query. Finally it was just a missing index, maybe a hickup in the upgrade or a missing migration, not sure.
So it was quite a bit of a journey and I hope this is the end of it
Sorry for any inconvenience!