MacRumors published a story that Apple has released macOS Catalina 10.15.4 Beta 5 to registered developers.
Apple Seeds Fifth Beta of Upcoming macOS Catalina 10.15.4 Update to Developers
Apple today seeded the fifth beta of an upcoming macOS 10.15.4 update to developers for testing purposes, one week after seeding the fourth beta and over a month after releasing macOS Catalina 10.15.3.
Apple Seeds Fifth Beta of Upcoming macOS Catalina 10.15.4 Update to Developers
The macOS Catalina beta can be downloaded using the Software Update mechanism in System Preferences after installing the proper software from the Developer Center.