WhatsApp has finally added support for some older mobile operating systems, including Windows Phone 7, as the company announced in mid-2016 that dedicated focus is enabled with the latest versions of Windows 10 Mobile, iOS, Android, and BlackBerry.
This means that users whose devices are powered by Windows 10 Mobile or up-to-date Android and iOS can continue to run WhatsApp on their phones. Additionally, Windows Phone 8.1 is fully supported by WhatsApp, despite its small market share.
WhatsApp's initial announcement in 2016 revealed that the company wanted to focus only on the most widespread platforms out there (thankfully despite a 0.5 percent market share, Windows 10 Mobile is not one of the operating systems WhatsApp is losing out to at the moment).
"As we look ahead to the next seven years, we want to focus our efforts on the mobile platforms that the vast majority of people use. So, by the end of 2016, we will have ended support for WhatsApp Messenger on the following mobile platforms: BlackBerry OS and BlackBerry 10, Nokia S40, Nokia Symbian S60, Android 2.1 and Android 2.2, Windows Phone 7, and iPhone 3GS / iOS 6," the company announced.
The company then reversed its decision for some platforms, deciding to extend support until mid-2017, but Windows Phone 7 is not included in that list.
"WhatsApp is extending support for BlackBerry OS, BlackBerry 10, Nokia S40, and Nokia Symbian S60 until June 30, 2017," WhatsApp announced in an update in late 2016.
WhatsApp is one of the companies that frequently updates its Windows Phone clients, and a beta program currently underway allows users to try out the improvements. Additionally, the Windows client is in sync with the iOS and Android versions, so most of the features available on those platforms are also included in the Windows 10 Mobile version.

