Download Macos 1012 Sierra Full [upd] Page

Apple provides the full installer for older versions primarily as DMG disk images

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If you try to download Sierra on a newer Mac (like an M1 or M2 MacBook), the App Store may prevent the download or give you an error message saying the software is incompatible with your machine. In this case, you will need a workaround. download macos 1012 sierra full

Apple still hosts the full macOS Sierra installer on its servers, but the link is hidden. Here is the direct, official link: Apple provides the full installer for older versions