Apple has ramped up internal testing of iOS 16.6 over the past week, according to a reliable source of information. This suggests the first beta version of the update will be seeded to developers and public beta testers in the coming days.
Apple confirmed that iOS 16.5 will be released to the public this week, so the first iOS 16.6 beta will likely be made available either later this week or next week. Apple has been internally testing iOS 16.6 since at least early April, and it will likely be one of the final updates in the iOS 16 software cycle, as Apple is expected to announce iOS 17 at WWDC next month and shift its development efforts towards that update.
iOS 16.6 will likely be a smaller update given that iOS 17 is on the horizon, but it remains to be seen which new features, changes, and bug fixes will be included. Apple previously announced that iMessage Contact Key Verification would be available in 2023, but it is unclear exactly when the optional security setting will launch.
iOS 16.6 should be released to the public in the weeks after WWDC, which begins June 5. There is no sign of Apple testing iOS 16.7 yet, but it's still early.
Source: Macrumors