Previewed at WWDC, launching in the fall.
Apple Seeds First Beta of iOS 11.4.1 to Public Beta Testers
Beta testers who are members of Apple's beta testing program will receive the iOS 11.4.1 beta update over-the-air after installing the proper certificate on an iOS device.
Those who want to join the beta testing program can sign up on Apple's beta testing website, which gives users access to iOS, macOS, and tvOS betas. iOS betas are not always stable and should not be installed on a primary device.
There were no notable features discovered in iOS 11.4.1 in the first developer beta, suggesting it focuses on bug fixes and other minor improvements.