I believe there's only one significant area that has changed, though there are a few elements that have changed. It relates to custom fields (which was mentioned specifically in the announcement).
- As an alternative to user_editable and moderator_editable, editable_user_group_ids is now an approach that can be used. This controls editability in a similar way to prefixes. (If you want to limit editing, this is likely to be a better option for any content-based custom field.)
- XF\Entity\AbstractField::setupDefaultStructure now has all options default to false. Opt into the approach you want.
- Template macro base_custom_field_macros:common has been renamed to common_options. The output should now be full form rows.
- In the base_custom_field_edit template, $generalOptions has been removed. Add to $extraOptions.
- While not a BC break, a getFieldEditMode method has been added to various field-containing entities to expose the edit mod more explicitly. There is now a "moderator_user" edit mode that represents when a moderator is editing/creating their own content (essentially a mix of moderator and user modes).
