I didn't go to Mysterium this year. I wanted to; it was held in Spokane, so the attendees got to visit Cyan's offices and chat with Rand and Robyn Miller and basically geek out all over the place. It didn't fit in with my summer plans, though. Fortunately the fans took copious notes. Here's the current Myst news:
Obduction development continues. Unreal 4 engine.
Cyan has posted a gigantic folder of Myst Online concept art (dropbox link). This is early material -- I'm guessing 2000 to 2002. A little bit of this wound up in Myst Online, and a bit more has leaked out online, but most of it is new to me.
A group of fans have gotten permission to work on Myst Online content -- updating areas from Myst 5, building areas from the concept art above, and importing original fan Ages. These may wind up in the official Myst Online server, although the final decision is up to Cyan, obviously. They say they're aiming to have something playable by the end of this year. I hope that works out. (More discussion in character.)
The Starry Expanse project (a fan remake of Riven) has made excellent progress building Riven's Jungle Island. Here's a video tour (youtube) of what they've done. You'll see that some textures are missing, and the water effects need work, but what they've got is fantastic.
Unwritten, the Myst-setting RPG, has been somewhat delayed but is making progress. They've shipped their Kickstarter tchotchkes; I have a nice D'ni-style notebook and some wooden tokens. (This is a Fate-based RPG, so there are Fate tokens.) The game manuscript itself has gone through a couple of rewrites, with input from Leonard Balsera. Last I heard they were aiming at shipping this month, but I get the impression it'll be another couple more.
There was a pancake printer. I don't know either.
Further notes from the convention:
Mysterium is back in Boston next year, and I hope to be there.