To see which version of Windows 10 your phone uses, on Start , swipe over to the All apps list, then select Settings > System > About > More info.
The Software section indicates the general product name (for example, Windows 10 Mobile). The Version section indicates which release of software your phone is running (for example, 1703). The OS build section indicates the specific build number of the software.
If your phone is currently running Windows Phone 8, see Update your Windows phone.