[Reeve of shinra]

In the past you could keep most of your modifications and customized templates during incremental upgrades (ie: 3.8.1 to 3.8.4).

That said, all mods had to be recoded when we went from vb2 to vb3 and many changes were required from 3.0 to 3.5. Some minor changes were required for the jump from 3.5 to 3.6 to 3.7 and 3.8 but as the code base remained fairly similar - it wasn't to big of a challenge to port the mods to the new version.

It was expected, and often mentioned, that the jump from 3.x to 4 would require a re-write of the modifications and templates. Unfortunately this error is on you here.

Where we (as customers) are uncertain, and where the vb team needs to step up, is about the changes that will break functionality between point releases in the vb4 series (ie: 4.0.1 to 4.0.2). That's a whole other mess and you can read about it in the many threads on vb.com.

Can you go back to 3.8? Only if you have a backup of the 3.8 database and are willing to lose anything added since then.

Going forward, it will be a good idea to test your upgrades first, including the minor updates during the early phases of vb4.