BAdIs are contained in the system and are fully operational as of Release 4.6B (for information on CRM products, seeInformation on Release Statuses in R/3 and CRM). They are activated as soon as an active implementation exists in the system. These implementations are imported into the system by transport requests, which a third party usually delivers. An implementation can be in an active or an inactive form in the transport request - usually, however, they are transported actively. If an active implementation has been imported, it is available in the system after all the steps relating to the transport have been carried out.
There cannot be more than one active implementation of BAdIs that are not intended for multiple use. If an active implementation already exists for such a BAdI (which is to be replaced), it may be a good idea to transport the implementation in an inactive form. For more information, see
The import and activation of add-ins are controlled using transactions SE18 and SE19. For more information, see the following in the SAP Library in Changes to the SAP Standard: