IPC does not use ECM numbers. However, you can generate multiple runtime versions of a knowledgebase that will be created for different validity dates ('Valid From Date' in cu34/35).For valid from date=X, the KB runtime version generation will include the ECM state of your characteristic valid at this date X - it's a 'snapshot' of your model data valid at X.
Hence you can apply model changes to the individual objects in ERP with ECM valid from X and generate a new KB runtime version valid from X to include the objects in this (new) state (e.g. with the characteristic having fewer values).The new runtime version is used for orders created with a target date of >= X.
