The Fall 2019 version of macOS. Catalina runs only 64-bit applications, and it is the first macOS version to support the Catalyst platform, which allows software to run on both macOS and iPadOS. In addition, the Sidecar feature enables an iPad to serve as an extra monitor and graphics tablet. Voice commands provide more control, and the Reminders app allows attachments. Find My Mac and Find My Friends are one app.
The Dashboard is dropped, and support for Perl, Python 2.7 and Ruby is deprecated. iTunes no longer handles all media but is split into separate apps. Catalina natively supports the PS4 and Xbox One wireless game controllers. See Mac OS X