3693331 - Is it possible to add custom field created in app Custom Fields to the IAM app?  - SAP S/4HANA Cloud Public Edition

- Create a custom field using the app Custom Fields in customizing tenant of development system. 
- Create an IAM app with ADT. 
- Is it possible to add this custom field to the IAM app? 

SAP S/4HANA Cloud Public Edition

The technical reason is "Only in SCFD_REGISTRY entered objects are extensible via Key User App "Custom Fields" and it's not possible to add or change SCFD_REGISTRY. ". 

It's not possible. 

F4 help, custom field, PO screen, MM_PURDOC_ITEM, SAP S/4HANA Cloud Public Edition, custom CDS views, ABAP Environment, CBO, Code List based on CDS View, Association to Business Object, Value Help, extensibility, IAM app, ADT , KBA , BC-SRV-APS-EXT-FLD , Custom Fields , Problem