2671173 - Error message: "Property attachment is not upsertable" when trying to upsert Attachment

You want to upsert an attachment through OData API into specific user's background, however you're getting an error:  "Property attachment is not upsertable"

Successfactors APIs - ODATA

1. In order for you to know if its possible to do an upsert for a specific field, you can go to OData API Data Dictionary.
2. We have verified that attachment is not upsertable for Background Entity as it is set to 'False'.
3. The attachment field of Background_Documents does not support to be updatable based on the current design, however, customer can open an enhancement for this in the influence portal.

SAP SuccessFactors HCM Suite OData API: Developer Guide
https://help.sap.com/viewer/d599f15995d348a1b45ba5603e2aba9b/latest/en-US

SAP SuccessFactors HCM Suite OData API: Reference Guide
https://help.sap.com/viewer/28bc3c8e3f214ab487ec51b1b8709adc/latest/en-US

SAP SuccessFactors Employee Central OData API: Reference Guide
https://help.sap.com/viewer/b2b06831c2cb4d5facd1dfde49a7aab5/latest/en-US

OData API, Attachment, Background_Documents, Background Entity, [COE0030]Property attachment is not insertable. Please check the property setting in Admin Center > OData API Data Dictionary or the entity metadata. , KBA , LOD-SF-INT-ODATA , OData API Framework , LOD-SF-INT , Integrations , Problem