From February 1, 2020, any iPhone running iOS 8 or older will no longer be supported, along with any Android device running version 2.3.7 or older. Users of these operating systems are already unable to create new WhatsApp accounts or re-verify existing accounts. WhatsApp is withdrawing support for all Windows phones from December 31, 2019 — the same month that Microsoft ends support of its Windows 10 Mobile OS.
WhatsApp said ‘because we no longer actively develop for these operating systems, some features might stop functioning at any time’. The Facebook-owned messenger service will continue to provide support for devices running Android 4.0.3 onwards and iPhones running iOS 9 and onwards.
Article: Daily Mail