This is Suresh comments at AGM Aug 2018 at 1.00.48 timeline, this comment makes me to think that Poet can be connected.
Anyways,I am not sure.. lets see.
The interposer does not change going from 100 to 400, once it’s done it can be applied to multiple protocols and multiple speeds. That’s kind of the beauty: We are not co-engineering these, we engineer them separately, and assemble known-good-die.