Apple seeded the third beta of an upcoming iOS 11.4.1 update to developers, one week after seeding the second beta and three weeks after releasing iOS 11.4, an update that introduced AirPlay 2 and Messages in iCloud. 

Registered developers can download the new iOS 11.4.1 beta from Apple's Developer Center or over-the-air once the proper configuration profile has been installed from the Developer Center. 

No new features were discovered in the first two iOS 11.4.1 betas, suggesting it focuses on bug fixes and performance improvements to address issues discovered since the release of iOS 11.4. 

We'll update this post should we discover any new features in the third iOS 11.4.1 beta, but we're not expecting major changes now that Apple has shifted its focus to iOS 12, which is also available to developers for beta testing purposes. 

Update: The third beta of iOS 11.4.1 is also available for public beta testers. 

Source: macrumors