In what is yet another nail in a firmly closed coffin, WhatsApp has announced that it will drop support for its BlackBerry app by the end of this year. The messaging app used by more than one billion people said it would end support for the once all-conquering smartphone, as well as older versions of Nokia, Android and Windows Phone software.Despite their gradual fade into obscurity, BlackBerry phones still have a following among fans of tactile keyboards and reliable e-mail services.David Cameron admitted to still using one last year, and Kim Kardashian has been a vocal supporter of the keyboard-enabled handsets.Though BlackBerry's most recent device, the Priv, runs Android, it was still releasing devices running its own operating system last year, so the (presumably small) number of people who bought one will be without WhatsApp in 10 months' time.When the messaging app, now owned by Facebook, was started in 2009, it was developed for BlackBerry and Nokia's Symbian, the dominant smartphone platforms at the time, and faced tough competition from BlackBerry's own BBM. Android, iOS and Windows Phone had less than 25% of the market.But the Canadian manufacturer's share of smartphone sales now stands at just 0.2%, according to Gartner, with smartphones running BlackBerry OS selling 1.7 million units.WhatsApp said mobile operating systems offered by Google, Apple and Microsoft accounted for 99.5% of sales today.WhatsApp said it had made a "tough decision" to stop supporting BlackBerry by the end of 2016."As we look ahead to our next seven years, we want to focus our efforts on the mobile platforms the vast majority of people use," it said.Perhaps most offensively for BlackBerry fans, WhatsApp recommended that users upgrade "to a newer Android, iPhone or Windows Phone before the end of 2016". As well as BlackBerry, WhatsApp said it would end support for Nokia S40, Nokia Symbian S60, Android 2.1 and 2.2 and Windows Phone 7.1."While these mobile devices have been an important part of our story, they don't offer the kind of capabilities we need to expand our app's features in the future," WhatsApp said. ..