Grand Theft Auto V is getting an update tomorrow and it's still not the Heists update.
Even after apologizing about the delay, Heists are still not available (it's been 322 days as of writing this).
The update we are getting tomorrow is the San Andreas Flight School update for GTA Online. It adds a bunch of new vehicles, both air and land, aerial solo challenges, and other things that Rockstar hasn't disclosed yet (how about Heists?).
The update will also change-up GTA Online gameplay. Payouts will be increased for the harder missions and you'll get more GTA$ for playing with others.
Expect more details on this update tomorrow, for now enjoy the Flight School video.
Have you given up on Heists in GTA Online? Let me know.