Apple recently said that it will stop non-enrollees of the Apple Developer Program from being able to download iOS 17 developer beta.

Beginning with the beta version of iOS 16.4, the Cupertino-based company will only make its ‘Beta Updates’ menu appear if the user’s Apple ID is signed on both the iPhone and their respective Developer Program account. The menu allows beta versions to be installed on an iPhone without having a configuration profile, and will be the only way moving forward.
The change now prevents non-enrollees to install the iOS 17 developer beta for free once released in June. This is to stop profiles from being downloaded on websites and installed without having to pay $99 annually. Those who do not wish to pay the program fee will have to wait until the public beta gets released to the public. It’s worth noting that Apple’s Beta Software program is free to join.