Following on from the release of iOS 11.4, Apple has released iOS 11.4.1 beta 1, the software has been released to developers at the moment.
Apple is also expected to release the iOS 11.4.1 beta 1 software to its public beta testing program some time soon.
The first beta of iOS 11.4.1 is now available from the Apple Developer Center and also as an over the air update for registered devices.
As yet there are no details on what is included in the first beta of iOS 11.4.1. The update probably includes a number of performance improvement and also bug fixes. As this is the first beta, we can expect it to be a while before the final version of the software is released.