At least under macOS 10.15 Catalina it is now possible to download complete installer files from old macOS versions via the terminal. In the following I will show you the command line required for this as well as a list with the individual versions of the old [...]
If you want to equip your old Apple Mac, iMac or MacBook with its original operating system or if you want to get an old collector's item working again after repairs, you need an appropriate installer. The installation file [...]