I’m a bit confused about firmware for Fez Cerberus. I’ve understood that now it borrow Premium libs, so no source code I imagine.
But is there a 4.3 firmware source code to work with ? I need to go directly with netmf 4.3 PK ?
Any link ? 
If you want to use the term “premium” then Cerberus is now premium. But we no longer use this term. All products are now the same, not open and they share the GHI extensions. Hydra is the only exception as highlighted in the news post.
As for source code, use the 4.2 sources and port to 4.3 if interested.
@ Gus - Thank you Gus. Ok I will look into this suggestion.