It's not happening, at least according to Mick Jagger. The singer told Britain's NME that "We're not gonna do Coachella, 'cos it's too early. There was a rumor we were gonna do that one, but it's very early, Coachella. It's April or something, isn’t it? And we're not gonna be ready to go by April. But we're not gonna stop."
The Stones themselves fueled the rumors when the tour section on their mobile app temporarily showed a live show in Indio, CA on April 12, the location and date for one weekend of the festival. The actual festival fueled the rumor with a mystery picture posted to Twitter that showed what seemed to be a round stone in the middle of the festival grounds (although some said it was actually a polo ball).
It seems that there will almost definitely be more Stones 50th Anniversary shows like those performed in London, Brookly and New Jersey over the last two months. Jagger said "I'm going to see what's on the table and discuss it with everyone. We'll announce it when we've figured it out. Really, all you're going to have to do is wait for an announcement."