Actually their was a transfer of S-400 technology
Thanks for correcting Thomas.
Coming up next after the wrap-up of KM-SAM(9M96 equivalent) is KL-SAM, functionally equivalent to 48N6. But it is not a 48N6, but actually a Ramjet missile; thus much lighter and more agile. So I guess Russians are trying to develop a new generation of SAMs with Korean money or something?
So Russia has no problem selling cutting-edge stuff to Koreans and this is why even PAK-FA is on the table now.