Have you noticed that once Apple releases a new version of the Mac operating system (macOS) that previous versions vanish from the App Store? Have you ever needed to reinstall one of these older versions of the Mac operating system (macOS)? It can be challenging to do this since Apple does not make older versions readily available unless you saved your own copy of the installer for the older version. I recently learned that some older versions are still available on the App Store.
This article on wphosting.tv has links for downloading some older versions of the Mac operating system (macOS). If you think you might ever need to install an older version then I recommend you download the installers now and then save the installer file so you can create your own install disk, if needed. This Apple support article currently provides instructions on how you can create your own installer disk for El Capitan, Sierra, High Sierra and Mojave. Alternatively you could use an application like DiskMaker X.
As of February 2019, Apple has links to get these versions from the App Store:
App Store links are not provided for older versions of the Mac operating system, such as El Capitan (10.11), Yosemite (10.10) or Mavericks (10.9). This is not a surprise since Apple only officially supports and maintains the 3 most recent versions of the Mac operating system (macOS).
Links are also provided for buying an installer from Apple for Mountain Lion (10.8), Lion (10.7) and Snow Leopard (10.6) Over the decades, Apple has vacillated on whether or not they charged for the Mac operating system. The most recent vacillation came with the introduction of OS X Mavericks (aka OS X 10.9) in 2013, when Apple switched to offering it for free. Prior to that, Apple charged for the Mac operating system since the introduction of Mac OS 8 in the late 1990’s.