The fifth beta version of iOS 11 lost one of the functions that allowed to free up extra space on iOS or Mac. With the release of the update, the storage of iMessage messages in iCloud is no longer carried out.
According to beta testers, Apple may return the function in the future, but for whatever reason it is not available in iOS 11 beta 5, it's unclear. Many have stored correspondence in iCloud, including "heavy" files, so as not to clutter up space on the iPhone or iPad, now the information can only be stored on the device itself.
There is information that Apple does not plan to return the function even in the release version of iOS 11, and it's really strange. Perhaps the messages are no longer stored in iCloud for security reasons, or the company's engineers are testing one of the new features.
In addition to innovations related to iMessage and iCloud, iOS 11 beta 5 has a new music icon in the Control Center, redesigned the camera and settings icons, and added improvements related to improving security and stability.