The iOS and iPadOS 16.5 betas are part of Apple's ongoing testing program for its operating systems, and the third releases are now available.
Developers can get the most recent releases from the Apple Developer Center by signing up for the beta testing program or by updating hardware that is already using the beta operating systems. Additionally, public beta versions of the releases are typically made available through the Apple Beta Software Program shortly after the developer releases.
AppleInsider and Apple strongly suggest users don't install beta operating systems or other beta software on "mission-critical" or primary devices, as there is the small chance of issues that could result in the loss of data. Testers should instead use thirdary or non-essential hardware and ensure they have sufficient backups of their critical data at all times.