In 11i there were API's (Update_Vendor, Update_Vendor_Site and Update_Vendor_Contact) but they were not supported in R12 due to integration with Multiple product teams. The reason being was that the entities Supplier, Sites and Contacts had representations in multiple products like TCA, IBY, ZX etc and all these representations needed to be in sync.
However, most of our customers have huge volumes of supplier data which they need to be able to control programmatically so the fact that they no longer had access to these API's was frustrating.
It was requested through Enhancement Request Bug 17575099: ENHANCEMENT FOR SUPPORT OF SUPPLIER UPDATE APIS that Oracle Payables provides API's for updating Supplier / Supplier Sites / Supplier Contacts in AP_VENDOR_PUB_PKG in R12.
Well, this functionality is now available and the following new APIs had been created:
*** Note: These are the only procedures supported to update suppliers, sites or contacts.
To download the document with additional information about these new procedures please review Doc ID 1618099.1 - New Supplier Update API's in Oracle Payables
R12: What are New Supplier Related Tables/Packages/Programs. APIs Supportability (Doc ID 812918.1)