I have created two trial systems, one with SLES 11 SP4 and another one with SLES 12 SP3, and I tried to register both systems with one free trial registration code that I generated this week on the customer center. My free trial code is from version 15 SP1 and I could successfully register SLES 12 SP3, but the SLES 11 SP4 gives the error "registration code invalid".
Why does it register only SLES 12? If I take a look at "Base And Extensions Products" of my free trial subscription on the customer center page, it gives me a list of all SLES systems since SLES 10 up to SLES 15.
Can please anyone explain how does it works?