Two weeks after the last release, Apple has made the fourth developer's beta of macOS Catalina 10.15.2 available for testing.
The fourth beta of macOS Catalina 10.15.2 is now available to developers enrolled in the Apple Developer Center. While not yet available, a public beta update will likely be issued later on Friday for users participating in the Apple Beta Software Program.
Apple's developer notes for the second and third beta releases note that the chief change is fixes to specific networking issues. Apple added the key website top-level domains .dev and .app to its implementation of the HTTP Strict Transport Security system to help safe browsing.
Both AppleInsider and Apple itself strongly recommend users don't install the betas on to "mission-critical" or primary devices, as there is the remote possibility of data loss or other issues. Instead, testers should install betas onto secondary or non-essential devices, and to make sure there are sufficient backups of important data before updating.