I was pulled off to another project for the last while. Now I have a question about one of the sites I have been working on in Drupal 9.
The documentation says only this about converting from 8/9:
Crossgrading from Drupal 8 or 9
We recommend using the same tools that would be used to go from Drupal 8 to Drupal 7 for Backdrop CMS: Migrate module, custom scripts, etc.
Has anyone any more info on this?