Customer-enhanced basic types are still supported after a release upgrade. SAP-standard successors to basic types from previous SAP releases are automatically combined with the existing enhancements. No manual maintenance is therefore required.
New IDoc types developed by SAP are supplied as new basic types. Manual maintenance on the part of the customer is not required after an upgrade.
Customer-defined basic types and any related enhancements are not affected by an upgrade. These customer developments, therefore, may require subsequent maintenance.