macOS Big Sur update
macOS Big Sur 11.6.8 - will there be no problem with iMovie on this update?
MacBook Air 11″, macOS 11.6
iMovie may be eligible for an upgrade. It's free. I haven't had any problems with it. If you are not already using the newest version, it's just different.
Creating a backup is a fundamental step included in Apple's macOS upgrade instructions. To learn how to use Time Machine please read Back up your files with Time Machine on Mac.