Apple released macOS Catalina back in October 2019. Earlier Apple released the fourth update 10.15.4 of the new macOS Catalina. The Catalina version 10.15.4 comes after a couple of months of releasing 10.15.3.
The users can download macOS Catalina from the Mac App Store using the System Preferences App. Apple also shared the release notes on the website. There are several additions to this new update.

Safari gets an update. According to the release updates, Content Blocker extensions delivered with Mac Catalyst apps are now available for use in Safari. The latest update also includes a screen time feature. With this feature now users can set communication limits to control who their children can communicate.
There are several App Store updates. Apple also adds several iCloud and Music updates. Apple also improves accessibility with this new update. Head pointer preference for moving a cursor on the screen based on the precise movements of your head.
There are also several bug fixes and improvements. It fixes an issue in Safari where a CAPTCHA tile may display incorrectly. It resolves an issue where Reminders may send notifications for completed reminders. It fixes an issue with screen brightness for the LG UltraFine 5K display after waking from sleep.