To update macOS High Sierra 10.13.6 to macOS Catalina 10.15, you must first , complete a full system backup using Time Machine , and then use a direct download link via Safari to fetch the installer from the Mac App Store .
Any application marked with a will not run on macOS Catalina. how to update macos high sierra 10136 to 1015
Once the download is complete, the installer should open automatically. To update macOS High Sierra 10