Research In Motion has released BlackBerry Messenger 7, adding new voice capabilities over Wi-Fi as it teases a BlackBerry 10 device on its websites around the world.

BBM 7 users will now be able to make free voice calls to their BBM contacts around the world over a Wi-Fi connection - sadly it doesn't look like 3G is supported. 

Previously in Beta for the last couple of weeks, RIM says over 80 per cent of testers said that they were likely to recommend BBM version 7 to their friends who where still using the service.

The new update also adds multi-tasking with split-screen so users can do other things while they talk, like check their email, as well as a stack of other more mundane features that are handy, but not essential.

BBM 7 with BBM Voice is now available for all BlackBerry smartphones running the BlackBerry 6 OS or higher with support planned for smartphones running the BlackBerry 5 OS early next year. The BBM 7 software update can be downloaded for free in the App World

Meanwhile, RIM is not forgetting about its future OS, which will be announced at the end of January 2013.

It has quietly uploaded a teaser picture on its website that shows what the back top corner of the new phone will be like. It's not much, but it is sure to get BB10 watchers excited.