Thank you for your answer.
I mean EAP-SIM has been described in 16 successive drafts, and finally became a RFC.
I don't know the content of the RFC itself, but I know that other AAA server (Cisco Access Registrar for example), performing EAP-SIM against SS7 network and HLR do need to upgrade in order to support latest release of EAP-SIM.

Thanks

Geof.