Following the release of iOS 13.1 beta 3, the Cupertinians rolled out the pre-release version of iOS 13.
Most likely, there will be no changes with the final release. Or they will be minimal. So you can safely install this beta version, it is the latest.
The size of the update is about 500 MB. Download iOS 13 GM can now authorized developers. The official release date is September 19th.
If you have iOS 13.1, then download iOS 13 GM “over the air” will not work. Need a separate firmware file