Until January 2021, the WhatsApp messaging app will stop working on some mobile phones because operating systems can no longer support the app.
In applications the application will be phased out and when that happens, it cannot be reinstalled. However, to resolve this issue, it will only be necessary to update the mobile phone software so that it supports WhatsApp.
In the Apple operating system, all iPhones running on PCs before iOS 9 will no longer support WhatsApp. In this case, the iPhone 4 (since 2010) will be the only device that will not update the new Apple operating system. All of the following models can get this setting, so the app can be accessed normally. The only change they need to make is to update iOS 9 to the latest version.
For Android, the most supported version of WhatsApp will be 4.0.3, launched in 2012. The recipient of the previous one cannot use the messaging application.
The effects will be felt later this week. It will be gradually completed in January. Until then, any bugs and security issues will be fixed.