Upgrade to High Sierra I currently run MacOS 10.12.4 Sierra on a mid-2011 iMac.  I want to upgrade to 10.13 High Sierra.  On the App Store, the only option (after Sept 24) is 10.14 Mojave.  Where should I go to get High Sierra?  If I go to https://support.apple.com/en_AU/downloads/macos,  there are many different download options, but they all are updates, such as 10.13.6.
macOS High Sierra Download Link

That link should permit you to download the full macOS High Sierra installer from the App Store.