BlackBerry phone owners using WhatsApp better find themselves a new favorite messaging app—or a new phone.

On Friday, the Facebook-owned FB messaging app announced on its blog that by the end of the year, it will cease support for a handful of mobile operating systems, including BlackBerry BBRY , Nokia S40, Nokia Symbian S60, Android 2.1 and 2.2, and Window Phone 7.1.

WhatsApp’s reasoning is that since its debut in early 2009, the mobile landscape has greatly changed. At the time, about 70% of smartphones ran on operating systems from BlackBerry and Nokia, which those from Google GOOGL , Apple AAPL , and Microsoft MSFT only made u 25%. Today, the latter three account for 99.5% of sales, says the company.

“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,” says the company.

Since Facebook bought the messaging app two years ago for a jaw-dropping $19 billion, WhatsApp has more than doubled its user base, and hit one billion monthly active users earlier this year.