Re: Is there a way to upgrade from Windows Phone 8.0 to 8.1 on my Nokia 520? Thanks!
Download the Preview for Developers app from the store, follow the prompts, make sure you have an active Microsoft account, sign in at the developer's site that it directs you to and then go back to the app and Enable it.
Once you do those steps you should be able to go to Settings > Phone update and check for the updates. Definitely recommend doing it over wi-fi and with the phone fully charged or plugged up. It will do several updates so it should take over 30-45 minutes. Once those are all done you should be good to go