There are not that many Windows- powered handset anymore, and the most popular Windows Phone version officially is not supported today.
Microsoft has announced it will stop supporting major updates to Windows Phone 8.1 from today. Previously, some of device users were supported to upgrades Windows 10 via Upgrade Advisor, however, there are more than 70% of Windows Phone users are using Windows Phone 8.1.
If users do not pay attention to their Windows Phone new, they might not have even notice they are eligible for an upgrade through the app. There some device cannot upgrade to Windows 10 for several reasons.
If you are still the outdated version of Microsoft’s mobile OS, you should check whether you can upgrade to Windows 10 or not. If not, you will receive no performance or security updates for your phone.