Edit and share movies at professional resolutions.
If you have previously purchased or downloaded iMovie (even a newer version) using the same Apple ID, you may be able to download the for your macOS, which might be 10.2.5 or close to it. download imovie 10.2.5
Various software archive sites (e.g., oldversion.com, filehippo, etc.) may offer iMovie 10.2.5 as a .dmg file. Edit and share movies at professional resolutions
Start a project on an iPhone or iPad and finish it on your Mac. download imovie 10.2.5