1. If choosing to bypass core meta tables, you may face issues with third party systems that rely on WordPress' core table structure (e.g; search plugins, database management plugins, etc.) If you find situations where this is a problem, please let us know so that we can investigate solutions.
2. If a table definition does not contain any columns, the table will not be created.
3. In cases where ACF JSON was enabled after field groups were created, you will need to save the field group again in order for ACF JSON to create the field group's JSON file. Without the field group's JSON file, data won't be handled correctly.
4. The use of hyphens in field names is supported but there are some considerations to be aware of. See Using hyphens in field names
5. Fields with the field name id, post_id, user_id, and/or _sort_order will result in errors as these are currently hard-coded, internal column names used by the plugin.
6. Some SQL data types are modified by WordPress and won't persist through to the SQL schema. Where necessary, a workaround is needed. See controlling column data types for details.
7. If choosing to store repeater field data in normalised tables, the id field is currently subject to change as a repeater's rows are reordered or removed. See working with repeater fields for more details.