Apple has just now started pushing iOS 9.3.3 beta 2 to registered developers. The second beta is released two weeks after first beta was released to developers and public beta testers.
As of now the update is available for registered developers only. Apple iOS 9.3.3 beta 2 will be released for public beta testers soon. The new update focuses on bug fixes rather than adding new features.
Apple has seeded the iOS 9.3.3 beta 2 for all compatible devices. The company has also released the beta update for iPad Pro 9.7 inch as well. Apple has fixed the error 56 bug for the tablet.
Registered developers can install the iOS 9.3.3 Beta 2 on their devices. The update will be released to public soon as next week Apple will showcase iOS 10 during WWDC.