It is; the question is, can you put the 24-core chips from IBM in the same socket? For that matter, what on earth is the socket name for POWER9 (or POWER8)?
After some more looking around, talking to someone on reddit.com/r/openpower, and looking at the new site information; the thought is that these are 50 mm × 50 mm Sforza sockets and the 4-core CPUs are 12-cores with 8 cores disabled.