Little Snitch 4.0 is highly compatible with OS X El Capitan through macOS Catalina.
Little Snitch 4 will not work on Big Sur or newer systems because it uses legacy "Kernel Extensions" that Apple no longer supports. Users on modern systems should download Little Snitch 6 (the current standard as of 2026) or Little Snitch 5 . Little Snitch 4.0 for Mac Free Download
Little Snitch 4 was designed for older versions of macOS. Compatibility is the most important factor when choosing which version to download: Little Snitch 4
If you are running an older Mac, version 4 introduced several major improvements that remain useful: Download Little Snitch - Objective Development Little Snitch 4 was designed for older versions of macOS
The visual Network Monitor typically expires after a 30-day trial period . Is Little Snitch 4.0 Right for Your Mac?
The network filter (firewall) deactivates every three hours . However, you can re-activate it as many times as you like.
When looking for a "free download" of Little Snitch 4.0, it is important to distinguish between the and outdated software versions. While Little Snitch 4 is a legacy version, you can still access its monitoring features for free through its built-in demo mode. The "Free" Version: Understanding Demo Mode