We try to keep Little Snitch 4 compatible with each new beta version of macOS High Sierra 10.13.
Known Limitations and Issues
During the Installation of Little Snitch on macOS High Sierra you may see an error message: “System Extension Blocked”. This is a new security mechanism in High Sierra, requiring you to explicitly allow the installation of a third party system extension. To complete the installation of Little Snitch you have to allow loading the extension in System Preferences > Security & Privacy > General.
There’s a known issue in the map view of Network Monitor causing connection endpoints to be shown twice.
For Beta 3 of High Sierra, you need at least Little Snitch 4.0.1 nightly, version 4.0 won‘t work.