Complex sentence: Messages sent via BlackBerry Messenger are sent over the Internet and use the BlackBerry PIN system, communication was only possible between BlackBerry devices until late 2013 when BBM was released on iOS and Android systems.
Split into simpler sentences: Messages sent via BlackBerry Messenger are sent over the Internet and use the BlackBerry PIN system. Communication was only possible between BlackBerry devices until late 2013 when BBM was released on iOS and Android systems.