Can you update Windows 8.1 for Lumia 520?

Yes, you can update a Lumia 520 to Windows 8.1. To do this, ensure your device is connected to Wi-Fi and check for updates in the "Settings" app under "Phone Update." If the update is available, follow the prompts to download and install it. Keep in mind that support for Windows Phone has ended, so further updates beyond 8.1 will not be available.