It's been a long time coming, but there's now less than a week left before WhatsApp stops working on certain BlackBerry and Windows Phone devices. The Facebook-owned firm previously announced it would be ending support for these platforms by the end of 2016, but it later extended the deadline.

In an update to its support page, the WhatsApp team writes that the ability to use the service on BlackBerry OS, BlackBerry 10, and Windows Phone 8.0 and older will end on December 31, 2017.

"Because we will no longer actively develop for these platforms, some features may stop functioning at any time," the company writes.

WhatsApp's end-of-life date on some other platforms won't be arriving as quickly. The few people still using Nokia Symbian S60 had their support terminated on June 30, 2017, but Nokia S40 support will go on until December 31, 2018, while Android versions 2.3.7 and older will be able to use the service until February 1, 2020.

"These platforms don't offer the kind of capabilities we need to expand our app's features in the future. If you use one of these affected mobile devices, we recommend upgrading to a newer OS version, or to a newer Android running OS 4.0+, iPhone running iOS 7+, or Windows Phone 8.1+ so that you can continue using WhatsApp," explains WhatsApp.

Updates for Windows Phone 7, Android 2.1, Android 2.2, and iOS 6 were stopped last year.

There's no option to transfer your chat history from one of the older platforms to a newer one should you upgrade, though WhatsApp does let you send them via an email attachment.

WhatsApp's decision doesn't come as a surprise. The number of BlackBerry OS and Windows Phone OS users combined make up less than 1 percent of the worldwide smartphone market.