MacRumors published a story that Apple has released the second beta of macOS Catalina 10.15.4 to the developers.
Apple Seeds Second Beta of Upcoming macOS Catalina 10.15.4 Update to Developers
Apple today seeded the second beta of an upcoming macOS 10.15.4 update to developers for testing purposes, two weeks after seeding the first beta.
Apple Seeds Second Beta of Upcoming macOS Catalina 10.15.4 Update to Developers