Apple has released iOS 11.4.1 beta version to registered developers. The update focuses on bug fixes and a new feature for homepod.
Now you can connect multiple homepod from your phone and there was little lag. Just a few days are left for WWDC event and Apple is pushing hard to resolve all the bug which was in iOS 11.
To update your Apple devices go to Settings > General > Software Update and if you are on beta tester then you have unrolled your device to update on 11.4 version.