Key details of
macOS Catalina 10.15.5
macOS Catalina features an updated Notes app with a new gallery view, designed to let you see all of your folders and Notes thumbnails at a glance. New tools let you manage folders and subfolders, and there are options for sharing an entire folder
Devloper's description
Devloped by Apple Inc.
macOS Catalina exclusively supports 64-bit applications. 32-bit applications no longer run (including all software that utilizes the Carbon API as well as QuickTime 7 applications, image, audio and video codecs). Apple has also removed all 32-bit-only apps from the Mac App Store.