Apple is completing the development of iOS 13, now reached the final phase: the iOS 13 Golden Master is available to developers. The Golden Master is the last version before Apple releases the final version on September 19. Developers can already download the iOS 13 Golden Master and soon the public testers will follow.
With the Golden Master, Apple is testing the latest version before it goes to the general public. The iOS 13 GM must prove that there are no more bugs in the software version. The beta period was quite noisy since Apple suddenly came out with the iOS 13.1 beta.
The iOS 13 GM is the same as the final version. If you are already on the beta version of iOS 13.1, then you need to downgrade to be able to download the new GM and the correct profile from the developer’s page.
Keep in mind that you are missing some features that are currently planned only for iOS 13.1 final version, therefore, for testers, it is recommended to stay on iOS 13.1 for now.
In most cases, it is safe to install the Golden Master. In recent years no major bugs or other problems have been discovered in the GM, so the final version is the same as the GM. To install the Golden Master officially, the beta profile for developers or public testers is required. You can still register as a public tester if you want to install the Golden Master as soon as it is available for public testers.
You can install the Golden Master by downloading the Restore Image via the developer page. Next, go to iTunes and click Check for updates while holding down the option button on your keyboard. Then choose the file from the GM that you downloaded earlier and proceed.
Note that you need the beta of macOS 10.15 or Xcode 11 GM for that to work.