Apple released a new round of betas for iOS 10.3 and macOS 10.12.4 Sierra today, which happened just five and six days before their predecessors, respectively. There are no new builds of watchOS or tvOS yet though, so those might show up later this week.
iOS 10.3 includes a few new features that you probably won't even notice, such as the addition of AirPods support to Find My iPhone. There are also new weather forecasts in Maps, improvements to SiriKit that allow you to make payments or order an Uber, and improvements to HomeKit and CarPlay.
The release notes don't show anything that's changed in this build, as they have the same fixes, notes, and known issues as they have in previous builds. SOS is still only supported in India, SiriKit car commands may not work as expected, and so on.
The macOS 10.12.4 Sierra release notes don't say anything at all, as usual. The update's main feature will be Night Shift, which tones down the amount of blue light emitted from your screen, which should help you to get a better night's sleep. You can also use Siri to check cricket scores, schedules, and player rosters from the Indian Premier League and International Cricket Council, and there's dictation support for Shanghainese.