Users of WhatsApp with older mobile phones may find that the messaging service no longer works on their device.

The Facebook-owned company announced that support for the operating systems of BlackBerry including BlackBerry 10, Nokia S40 and Symbian S60, Android 2.1 and 2.2 and Windows Phone 7.1 will end this year.

With more than one billion people now using the messaging service, the company said in a blog post on their website that they want to focus their efforts on the "mobile platforms the vast majority of people use."

"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," the company said in the post.

"This was a tough decision for us to make, but the right one in order to give people better ways to keep in touch with friends, family, and loved ones using WhatsApp."

When WhatsApp started seven years ago more than 70% of smartphones sold at the time had operating systems offered by BlackBerry and Nokia.

But as of 2016, more than 99.5% of operating systems used on mobile devices are now offered by Google, Apple and Microsoft.

WhatsApp has recommended that those with affected devices upgrade to a newer Android, iPhone or Windows Phone before the end of 2016 to continue using the service.