Apple has released a new fifth developer beta of iOS 11.1, along with the fourth betas of macOS High Sierra 10.13.1 and tvOS 11.1. They can be downloaded from the Apple Developer Center or through the Software Update mechanism in the Mac App Store with the proper profile installed.
Also, there’s a new public beta of macOS High Sierra 10.3.1 available for public beta testers. If you’re not already signed up for the public beta program, you can do so at https://beta.apple.com/sp/betaprogram/ . The public beta program is free, but remember: beta software is unfinished software so use with care.