While the release date for Windows 10 is approaching, Microsoft has not yet clearly stated which devices can be upgraded to Windows 10 Mobile and which will remain in Windows Phone 8.1.
There are some Lumia smartphones that the company has confirmed to be compatible with Windows 10 Mobila.
Some have also been announced by manufacturers (OEMs), but Microsoft has not yet announced the minimum upgrade requirements.
But the WindowsMania.pl website is reported to have acquired a Qualcomm list showing compatible phones with the upcoming Windows 10 Mobile.
According to the table, if your Lumia smartphone is equipped with one of the listed Qualcomm chipsets, it is eligible to upgrade to Windows 10 Mobile.
See the list of chips supporting the upgrade