An announcement on OutKast's official website states that,
"After headlining performances at Coachella in April, the influential group will be the marquee act at over 40 festivals around the world throughout the Spring/Summer of 2014 (dates to be announced)."
This announcement is backed up by the newly-created OutKast Twitter account, which also provided quotes from both members on the upcoming tour:
Returning to the stage together is the most exciting way for us to thank everyone for 20 years of supporting Outkast. -Andre 3000 #Outkast20
— Outkast (@Outkast) January 13, 2014
I'm looking forward to rocking the stage with my Bro Ski and to all the fans - stank you smelly much, this is for y'all! -@BigBoi #Outkast20
— Outkast (@Outkast) January 13, 2014
Apart from Coachella and NYC's Governors Ball, no other festivals have been named as dates on OutKast's upcoming tour. We'll keep you posted as more details arise. For now, rejoice in knowing that OutKast will most likely be coming to a summer music festival near you in 2014.
Source: OutKast.com