BlackBerry Key2 teaser reveals mystery button, dual rear cameras

BlackBerry has announced the date for its upcoming BlackBerry Key2 smartphone unveiling. The company wasn’t content leaving us in the dark, so it published a short teaser showcasing a few features users can expect. There are dual rear cameras, for example, as well as a physical keyboard. Most interesting, though, is the handset’s new mystery button. The BlackBerry Key2, at …