Rob Kardashian & Blac Chyna On Speaking Terms Again for Dream

Rob Kardashian and Blac Chyna weren't faking it when they exchanged Twitter pleasantries -- the two are actively communicating and repairing their relationship ... for Dream's sake.

Sources close to the former couple say they underwent at least 7 mediation sessions together to iron out a deal for custody of Dream, and they've continued to be in direct contact about their daughter's care. Translation: for the first time in a LONG time Rob and Chyna are cordial.

We're told the goal is for Rob and Chyna to make face-to-face handoffs of Dream. Of course, they'll still have nannies standing by to assist sometimes.

As for the physical custody of Dream -- Rob will have her for the majority, but they'll be splitting holidays equally and finding ways to accommodate both parents' schedules.

We're told they came to an understanding, during mediation, that neither would bring a new significant other around Dream unless it was a long term, healthy relationship.

As we reported, Rob was previously forking over $20K per month in child support, but that number has been reduced.