More markets in Europe and Asia, like Hungary and Taiwan show Lumia Cyan available for Lumia 1520 in the tracker. Post Lumia 625 and Lumia 925, which received Lumia Cyan en masse, Lumia Cyan has been rolling out to Lumia 1520 in India, Finland and even UK. Even AT&T has become the first US carrier to go ahead with the update. So, keep checking for the update on your Lumia 1520 and you may get lucky.
You may like to read some of earlier posts for any help required,
[Running Developers preview & BitLocker encryption, need a software rollback before updating to Lumia Cyan]
[Just updated to Windows Phone 8.1 (Lumia Cyan)? Here is your guide to Niravana!!]
For catching everything about Lumia Cyan and Windows Phone 8.1 which includes:- Full Changelog, Hands-on demo videos, Tips, Tutorial no better place than our dedicated Lumia Cyan and Windows Phone 8.1 page.