Download code needed for updating to macOS Sierra GM When I click on the GM download link it asks for a download code or a gift card number? I already have a developer license. Where do I get the download code. I have already installed and use the last Developer Beta.
You'll need to go to the Apple Developers download page and click on the Download button next to macOS 10.12 GM Seed.

If you already did so and signed into the app store to redeem your code then your redemption code should be visible underneath that line.