Windows 10 upgrade doesn't resolve Lumia 640xL's issues.
Windows 10 upgrade doesn't resolve Lumia 640xL's issues.
You need to be an Insider to obtain Windows 10 Mobile. Regardless, I strongly recommend joining the Insider program for Windows 10 Mobile. Check the store for the Insider app. Also, Windows 10 Mobile is now available. It won’t receive Redstone 3 from this channel. Considering Microsoft’s stance, you might need a Surface Phone. Possibly, the Lumia 950 / 950 XL and HP Elite x3 could work if they meet the requirements, thanks to their powerful processors and ample RAM. However, the 950/950XL may be the bare minimum for the OS, so it’s not ideal. We should keep an eye on things and confirm if this is official.
Your 640XL ran smoothly on Windows 10. People say the Upgrade Advisor isn't functioning now. Consider testing it under Windows Insider. Please stay calm and proceed carefully.
Microsoft resolved the Windows Update Advisor issue. Give it a try! (The app may require an update beforehand—I don’t know... I don’t have WP8.)