According to Macrumors, the next update from Apple’s side appears to be iOS 16.3.1, which means that it will be a while before it’s time for iOS 16.4.
The focus in IOS 16.3.1 is on bug and security fixes, but there are many indications that we will see a number of new features in IOS 16.4.
Among the expected features can be mentioned new emojis (Unicode 15), web-based push notifications, Apple Pay Later and savings accounts on Apple Card.
Additionally, we may see Apple Music Classical, a new app for classical music that would have been released in 2022.
Sharp version of IOS 16.4 is expected in March or April.