After the release of iOS 16.4.1 on April 7, Apple closed the verification channels for the previous iOS version, iOS 16.4, making it impossible to downgrade to these versions after upgrading to iOS 16.4.1. To encourage users to keep the operating system updated, Apple typically closes the verification channel for the previous version shortly after the release of the new version.
According to the reports, currently, iPhone users experience the latest version of the iOS update. Apple recently released iOS 16.5 beta 2 along with iPadOS 16.5 and macOS 13.4. According to the previous report, iOS 16.4 was introduced on March 28 which fixes minor bugs including security improvements.
However, I assume that neither iOS 16.5 nor iOS 16.6 will introduce significant new features, with the possible exception of an update to iOS 16.7, which, as has been the case in recent years, should not significantly alter iOS.