Diagnosis
If a server does not yet know a business partner group, the group andthe addresses of all group members have to be downloaded for alladdress types supported.
If the server already knows a group, but the group is obsolete and hasbeen downloaded again, only the addresses that the server does not yetknow have to be downloaded for those address types that are alreadysupported. The delta is, therefore, requested after the group has beendownloaded. All addresses have to be downloaded for all new addresstypes that are to be supported.
If a server already has the current version of a group, and thereforeno delta exists, all that has to be determined is whether new addresstypes that are to be supported have been added. If so, all addresseshave to be downloaded for these address types. For address types thatare already supported, no addresses have to be downloaded.