Hello Syed Sharafi Sakib
Thanks for raising your concerns in Microsoft Community.
Unfortunately, Windows phone operating systems are no longer supported by Microsoft.Windows 10 Mobile support ended on December 10, 2019 and Windows Phone 8.1 support ended on July 11, 2017 . This means that these devices will not receive any security or fe nature updates, and some services and apps may stop working. This also includes previously official upgrade tools and support sites.
Therefore, Microsoft recommends that users upgrade or migrate to other operating systems such as iOS or Android for a better experience.
Thank you for your understanding and support!
Best regards,
Chandy |Microsoft Community Support Specialist