Apple releases first beta versions for iOS/iPadOS 16.6, macOS 13.5 Ventura, watchOS 9.6, tvOS 16.6.
Not much is know regarding updates in this set of beta versions. It seems that this release should enable iMessage Contact Key Verification.
Beta download: Operating Systems
Release notes do not contain any information so far.
Apple Developer: Get ready with the latest beta releases
Reference: iOS 16.6 Beta Lays Groundwork for iMessage Contact Key Verification