Relatively more or less at same time.
Functionality for both will be the same. Which includes the MOL2 and as well as the receiver's user interface and specs and etc, etc
I had to add another thought...
There is one difference (other then the name). And that is their onboard app Markets.
The Dreamlink's onboard apps Market is catered more so to North American users (but not entirely).
The Dreamlink devs/techs will take requests for additions to the onboard Market. you can do that here at iptvtalk and thru Captain.
While the Z8 Market is catered more so towards Euro users.
The devs/techs from Dreamlink and Formuler(z8) create and load their individual puplic Markets, so they are quite different from each other concerning content.