Facebook-owned mobile messaging app WhatsApp has stopped working on smartphones that support 'BlackBerry OS', 'BlackBerry 10', 'Windows Phone 8.0' and older platforms in the New Year."These platforms don't offer the kind of capabilities we need to expand our app's features in the future," a spokesperson wrote in a support note on the company's website."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," it said.Users would be able to use WhatsApp but would not be able to create new accounts or re-verify existing accounts."Because we will no longer actively develop for these platforms, some features may stop functioning at any time," WhatsApp said.WhatsApp would also end support for Nokia S40 after December 31, 2018 and Android versions 2.3.7 and older after February 1, 2020."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," the company said."If you use one of these affected mobile devices, we recommend upgrading to a newer Android, iPhone, or Windows Phone to continue using WhatsApp," it added.