Hi Thomas,
For Installed Base Management, the replication from ERP is available for Equipments - replicated as Registered Products in C4C and Functional Locations - replicated as Installation Points of type Functional Location in C4C.
If what is available is not enough, in general it is possible to enhance C4C and adapt the iFlows accordingly.
In case of upgrades, the extended IDOC can be used in place of standard IDOC while retaining the mapping provided by SAP for standard elements. This is possible in HCI. You can refer to this blog for more details:
The following link has consolidated information on Cloud for Customer Integration:
You can go through this FAQs on Installed Base Management -
Hope this helps.
Regards,
Anshika