Millions of smartphones will lose access to popular instant messaging platform WhatsApp as of Monday. More than 40 smartphone models will be unable to use the <a href="https://www.thenationalnews.com/arts-culture/2021/10/29/facebook-is-now-meta-and-the-internet-has-something-to-say-about-it/" target="_blank">Meta</a>-owned app, which will stop working on systems that are older than Android OS 4.1, Apple's iOS 10 and KaiOS 2.5.1, according to its FAQ section. This means the phone will be incompatible with WhatsApp if you're running an older system. This includes popular devices such as the Samsung Galaxy S3, Huawei Ascend Mate and iPhone 4. See a full list <a href="https://www.thenationalnews.com/arts-culture/2021/09/05/whatsapp-to-stop-working-on-43-smartphone-models-from-november/">here</a>. If this includes your device, you'll need to upgrade to a newer model of phone that has an operating system the company supports – or use a <a href="https://www.thenationalnews.com/arts-culture/the-best-whatsapp-alternatives-signal-telegram-and-other-messenger-apps-to-try-1.1144346">different messaging service</a> altogether. For some devices, including the iPhone 6s or first-generation iPhone SE, all users need to do is update their systems to the latest iOS 15 in order to continue using the messaging service. Anyone switching from Apple to Android will also be pleased to know there's a feature that allows users to migrate chats between devices. Previously, before an update in September, iOS chat histories would be stored in iCloud, while Android histories went to Google Drive, making it nearly impossible to transfer chats between phones that use different operating systems. Users would be advised to instead email their chat histories to themselves. The new feature encompasses voice messages, photos and videos, but not call history or display name. "To start, this feature is available on any Samsung device running Android 10 or higher, and will be available on more Android devices soon," said WhatsApp. It's common for apps to stop working on older devices, often because it's not cost-efficient for technology companies, particularly if a device has a small customer base.