Apple on Wednesday seeded iOS 10.3.3 beta 6 to its registered developers and members of the paid Apple Developer Program. The new update has a build number of 14G57 or 14G58, depending on the device. It can be deployed to any compatible iPhone, iPad or iPod touch via the Software Update mechanism in the Settings app.
Your device must have an appropriate configuration profile installed, which can be downloaded from Dev Center. The latest beta arrives following iOS 10.3.3 beta 5, which was seeded to developers on June 28 (the first beta dropped on May 16).
Some of the fixes in iOS 10.3.3 are mentioned in Andrew’s walkthrough video of the first beta.
As mentioned, iOS 10.3.3 is a bug-fix release which enhances the security and performance of your iPhone, iPad and iPod touch. This is most likely that last point update to iOS 10 as Apple continues to beta-test the major iOS 11 software update ahead of its public release in the fall.
Apple also released macOS Sierra 10.12.6 beta 6 for developer testing today.