BlackBerry is calling BBMs release on Android and iOS one of the best single-day openings for a mobile app ever, after it landed 5m downloads in eight hours, and 10m after the first day.

The messaging app was originally supposed to see release on non-BlackBerry platforms a few weeks back, but was subsequently plagued by delays. It seems this hasnt diminished users appetite, however, with the app ranked as the number one free app on the App Store in 75 countries.

“The mobile messaging market is full of opportunity for BBM,” said Andrew Bocking, executive vice president of BBM at BlackBerry. “We intend to be the leading private social network for everyone who needs the immediate communication and collaboration of instant messaging combined with the privacy, control and reliability delivered through BBM.”

Itll be interesting to see how the app competes with supremely successful OTT apps like WhatsApp, Line and KakaoTalk over the coming months.