https://wccftech.com/macos-catalina-beta-4-released-to-developers-for-testing-purposes/

Today, Apple has seen fit to release macOS Catalina beta 4 to developers for testing purposes. It might be too early to anticipate any forward-facing additions, but let’s see what the new beta build has in store for developers. Apart from this, macOS Catalina beta 4 arrives two weeks after the third beta was released and over a month after the initial debut of the build at Apple’s WWDC 2019. Let’s dive in to see some more details on the latest build and how you can install it on your supported machines.

If you’re a registered developer, you can download the latest macOS Catalina beta 4 on your supported Mac devices using the Software Update mechanism in System Preferences. Since it is an early build, we would recommend you to not install it on your daily driver because of the hefty bugs that it is carrying. There are several changes made in firmware, which users might already be familiar with.