An iOS MSDK or UX SDK based application does not need an MFi recert whenever there is a new app version update or a new DJI SDK version is released. An app generally will only need an MFi recert if the app name or bundle ID changes.

For more details refer to the SDK documentation here: https://developer.dji.com/mobile-sdk/documentation/application-development-workflow/workflow-deploy.html#mfi-authorization

-Lisa, DJI Developer Support

Generally, apply for MFI certification before uploading app to the app store.