in the Mac App Store, getting this specific older version requires a specific workaround through your purchase history. Apple Support Community How to Download Older Versions
: A prompt will likely appear stating that the current version is not compatible with your OS. It should offer to download the "last compatible version" for your specific system. Apple Discussions Compatibility Notes macOS Catalina (10.15.7) : iMovie versions are known to be compatible with this OS. macOS High Sierra (10.13) imovie 10.1.12 download
. Apple typically doesn't provide standalone DMG installers for specific older versions, but you can trigger a download of the last compatible version if you have previously "purchased" (downloaded) iMovie with your Apple ID. How to Download iMovie 10.1.12 Open the App Store : Click the Apple icon in the top left and select Go to Purchases in the Mac App Store, getting this specific