Briefly mentioned in the JLI interview:
Nrama: You mentioned that some characters are busy "elsewhere," and the solicitation didn't mention Booster Gold. But it just seems odd to have "Blue" there without the "Gold." We know Booster is in Convergence somewhere. Any chance for a reunion?
Marz: Booster plays a pivotal role in Convergence as a whole, so there are quite a few demands for his presence across the event.
That said, however, you're right — it seems like there should be some sort of Blue and Gold moment, doesn't it?
Yeah but aren't there more Boosters? Well it's nice to hear that Booster has a pivotal role and a lot of demands for this event.