Through BBM Voice you can call any BBM contact for free via Wi-Fi or cellular data. Meanwhile Channels is Blackberry's sort-of-social-network that lets you "follow" topics and chat with other BBM who share that mutual interest.
The update also throws in Dropbox support to let iOS and Android users send files directly to other BBM-ers. All very handy stuff.
- Just how good is BlackBerry's latest OS, BlackBerry 10?