After iOS 16.2 was officially released to the public, Apple started seeding the first developer betas for iOS 16.3, iPadOS 16.3, macOS Ventura 13.2 and tvOS 16.3. Users with developer beta access can download the new builds immediately. To do this, simply start the software update in the iOS settings.
New features in iOS 16.3 also include new security keys. These work with FIDO-certified physical security keys to verify and log into websites and devices. The new feature is also available for iPadOS 16.3 and macOS Ventura 13.2 users. Other new features in iOS 16.3 include an Apple Card Savings Account, Apple Pay Later, Apple Music Classical, Custom Accessibility Mode, and Advanced Data Protection for iCloud beyond the US.
The official release of iOS and iPadOS 16.3 is expected to happen in February/March 2023. As usual, caution is advised when dealing with beta firmware updates. You should back up both the devices and personal data beforehand and best avoid installing it on your primary devices.