Blackberry has finally announced the official dates for when BBM will go cross platform and its close.
BBM will be available for Android first on September 21st and for iOS on the 22nd and this will be a global roll out. Blackberry Messenger will allow Android and iOS users the ability to communicate with owners with Blackberry’s, as well as delivery, read, and typing notifications. It also lets users share files, images, and voice notes, and supports group chats with
up to 30 people.
BBM will support Android 4.0(ICS) and above and will support iOS 6 and 7.
Source: Blackberry Blog