as we plan the PI upgrade from 7.4 dual stack to 7.5 single stack, I was wondering if it is possible to have 2 production PI systems (environments) in parallel. The plan is to create 7.5 as separate systems (DEV, QA, PRD) and then continuously migrate interfaces from 7.4 to 7.5.
My question is, is this possble? For example scenarios with client ABAP proxies. Let's imagine I have some of interfaces migrated, some not yet. How will SAP ECC know, to which PI system to forward the requests to? (The same for example for RFC calls from ECC to PI)
Or do we need to migrate interfaces and then do a big-bang switch from 1 PI system to the new one?
Thanks for help,