Windows 10

[Vishnu YV]

No windows 10 update for Lumia 520??

 

[Maurizio Troso]

No windows 10 update for Lumia 520??

Google for official Microsoft Win10 mobile release news on March: you'll find eligible phones. Sorry, 520 wasn't (too low RAM).
Only way for you to get Win10 Threshold is joinin Insider via Release Preview Ring:

http://forums.windowscentral.com/wi...discussion-threshold-branch-release-ring.html

Remember, it isn't snappy as Win8 on a 512 MB device limited