My previous topic was closed so I cannot post there.
I wanted to point out that I tried upgrading to v. 2.0.0.6 and using the old Classic Theme but that theme does not retain all the customisations I had applied.
Leaving this here in case other people encounter the same issue.
Please forget about the old theme. We've already mentioned tons of times that you'll lose all customizations. Even there are sticky topics on the forum top, there is an info in the major version update instruction, in the plugin changelog, there are lots of information on almost everywhere.
The answer is simple, we don't support the old theme anymore, and you have not chance to retain the old theme customization on v2.0, it's just impossible, because wpForo 2.0 is totally different plugin, even the classic theme is not the old one, it has been changed to work somehow. But it is out of the support either. We left it only to give you time to switch you to 2022.