Messaging service WhatsApp will stop working on millions of phones in the next few months, as the company withdraws support from older devices.From February 1, any iPhone running iOS 8 will no longer be supported (and users are already unable to create or verify their accounts on these devices).On the same date, Android devices running version 2.3.7 or older will have support withdrawn.From December 31, all Windows phone users will be unable to use Whatsapp.Facebook, owner of WhatsApp, said in a blog post: "WhatsApp will stop working on millions of phones in the next couple of months as the company withdraws support for some older mobile platforms."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."Furthermore, 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."Facebook bought Instagram in 2012 for $1 billion and WhatsApp in 2014 for $19 billion, and the two form part of the "Facebook family of apps", alongside the main Facebook app and Messenger.Earlier this year, Facebook announced plans to integrate its messaging apps more closely, alongside a move towards end-to-end encryption across its services.At the time, Facebook founder and chief executive Mark Zuckerberg said the plans were part of an effort "to make it easier to reach friends and family across networks".