Probably just working on new music. Has it even been that long since their last release?
ETA: from wiki...
The group toured throughout 2012 but planned to dedicate part of the year to writing and recording their second album. Foster said, "Hopefully we'll have a song or two out by the end of the year... I'd like to get the album done pretty quickly but we're not going to put something out until it's ready... I'd say in 2013 it'll be out." By the time the group's final US tour for Torches concluded in Las Vegas in July 2012, the group had played 295 shows in the previous 16 months.