Nokia Lumia 525 is not updating to Windows 10 [duplicate]

Question

My Nokia Lumia 525 is not updating to Windows 10 Mobile. What is the problem and how can I resolve it?

Answer 1

Although Microsoft first planned to upgrade all the Windows Phone 8 devices, they recently stated that only some devices will get the upgrade. Here's the actual list :

Source

Unfortunately, as you can see, the Lumia 525 is not eligible.