Apple has seeded the second beta build of iOS 10.3.3 to both their developer and public beta testing communities today. The update is available for download for those with registered iPhones and iPads that are compatible with the update. This second beta does not bring any new features and focuses on overall performance and bug fixes.
While it is not clear when 10.3.3 will be released, it will likely be soon for a few reasons. First, this is very much a maintenance release and with the exception of a new wallpaper for the iPad Pro 12.3″, there is nothing new to be found. Second, and perhaps more importantly, WWDC starts next week.