I don't have the exact answer to your question but I asked myself the same thing.
According to product specs:
5‑pin XLR talkback headset connection for talkback on channels 15/16 in the SDI and 2110 IP video.
So talkback is handled the same way than before: by using channels 15 and 16 of the SDI signal.
Which mean you can theoretically transmit intercom using two mini converter, or any product from BMD which handle talkback (Talkback Convertor, Constellation, etc...).