Hi,

yes, it works ... and it's recommended if you upgrade too fast in production site.

BACKUP first.

Clear Joomla cache after.

Thanks !

i will give it a try.

How do you downgrade it back to 3.8?

I downgraded back to 3.8.8.
The result is a broken site. This is the error:

Attempt to assign property "cssClassName" on array

Any ideas?

Not yet, but I asked our developer for help.

I guess, You don't have backup before upgrade date?

@Ronny

I talked with the developer - the only way to fix broken pages, is to export them from the backup site, when you still had SPPB 3.8x and import to current website OR keep using SPPB 4.x. It's becuase when you opened page in SPPB 4.x page code structure changed. No hidden tricks/fix this time, sorry