Upgrading from 1.6.0 to 3

So i was able to restore succesfully to a new digitalocean droplet - didn’t need to ditch the custom themes in the end.

I’ve got most everything running, except for a bug i’m seeing when i try to edit an existing category

I get a Server Error while trying to load /c/xxxx-xxxx-xxxx/find_by_slug.json
Error code 500 error

I also cannot create new categories - 500 error
and i cannot re-order categories..