imovie for OS10.14.6

You may not be able to upgrade from iMovie 8. I don't believe there is any path for doing so.

However, try the following procedure and see if it will work to get the highest version of iMovie that Mojave will run. It usually requires that you have. or have had at one time, a version of iMovie 10 on your Mac. Still, it is worth a try.

To update/redownload iMovie 10, drag your iMovie 10 app (or in your case, iMovie 8) from the Applications

folder into the trash, but do not empty the trash. Sign in to the app store and open your purchases folder by clicking on your name at the bottom of the app store side bar. You will see your purchases displayed, including iMovie 10. Redownload/update

iMovie from there. If not successful, drag your present iMovie app out of the trash and return it to the Applications folder.

-- Rich

That's great! I wasn't sure it would work. So, did you ever have iMovie 10 on your computer, but maybe deleted it, before you did the download procedure? Or did you never have it but it updated to iMovie 10 anyway?

-- Rich

It should do if you carry out the instructions posted by Rich.

" To update/redownload iMovie 10, drag your iMovie 10 app (or in your case, iMovie 8) from the Applications

folder into the trash, but do not empty the trash. Sign in to the app store and open your purchases folder by clicking on your name at the bottom of the app store side bar. You will see your purchases displayed, including iMovie 10. Redownload/update

iMovie from there. If not successful, drag your present iMovie app out of the trash and return it to the Applications folder. "

Also, Apple say that system requirements for iMovie 10.2.1 is Catalina or later.

Did you have to upgrade from Mojave to Catalina to get 10.2.1?