Before registering DOIs with mEDRA or DataCite for the first time you’ll have to decide whether you want to use the registration connector in “manual export” or “automatic registration” mode. This depends above all on your relation with the registration agency:
While, in principle, it is possible to mix both modes of operation, you should not usually do so. If, for example, you configure the DOI connectors for automatic registration and then upload a file manually to the registration agency you’ll end up in a situation where the OJS registration database is out of sync with the registration agencies’ database. This can lead to registration errors when trying to update metadata of an object that has been registered manually before. This is especially important when you work with mEDRA as the mEDRA XML format (O4DOI) differs for initial registration and metadata update.
It is not problematic, though, to use the XML export feature for local inspection of XML data that will be transferred to the registration agency via OJS later. As long as the actual registration is done in OJS, the local and remote registration databases will not get out of sync.