Upgrading custom plugins from Capacitor 3 to Capacitor 4

I cannot find any official documentation on upgrading custom plugins (not apps) from Capacitor 3 to Capacitor 4. The CLI command npx cap migrate seems to only apply to app projects.

Could someone share the specific steps involved?

I don’t think there are any mandatory changes, only recommended changes, such as setting the deployment target to 13 for iOS, use target/compile SDK to 32 for Android, updating gradle and the dependencies to @capacitor packages to ^4.0.0

All the changes we did are condensed in this change to the plugin template

There is this package that automates those changes with a single command

npx @rdlabo/capacitor-plugin-to-v4