1979 I. R. is the "default" date for the Domikka campaign and fiction setting.
Murder on the Hot Flats my upcoming 8,000 word story, takes place in the summer of that year.
Anything I published before that date is considered "canon," anything after "expanded universe."
If I publish a campaign "sourcebook," it'll be more like the old World of Greyhawk campaign boxed set. Here's a bit of history, some special rules, a bit of geography, some cool maps, and... go!
While I have no idea if it'll ever come to this, I never want Domikka to be a haven for fans (both readers and RPG players) to push canon on other players and referees. That's one of the things that irked me about the Forgotten Realms. Yeah, sure, it was and still is the most comprehensive campaign setting out there, but I knew I lot of players felt compelled to stick with what was written in the fiction books.
It was like if you hadn't kept up with the fiction or rules supplement, you were being left out. And, in the few times I played in a Forgotten Realms game, I got annoyed at the local Realms Loremaster--"Oh, how can you not know about 'spellfire?'"
I also don't want to "blow up" Domikka, like what happened so many other fantasy settings, like both Dragonlance and the Forgotten Realms. I rolled my eyes at WotC's announcement of "The Sundering" for the Forgotten Realms at Gen Con 2012.
Why can't they do something cool, like team up with Games Workshop to have Space Marines invade the Realms?