Google plans to stop providing the Realtime API capabilities for Google Drive files to third parties (such as MindMup). The change will take effect from December 11th 2018, according to their announcement. This most likely means that, from December, MindMup users will have to choose between keeping their maps on Google Drive and collaborative editing.
Starting from 27 February 2018, MindMup provides a suitable replacement service with safe concurrent editing and collaboration on our MindMup Cloud storage, available to all Gold users at no additional cost. Users can now share maps privately with other Gold users, and organisational users can create both private and team maps (shared with the rest of the organisation). Over the next few months we plan to significantly improve this service. If you are currently storing maps on Google Drive, and want to try out the new platform, just point your browser to https://app.mindmup.com instead of https://drive.mindmup.com when starting to edit maps. You can still sign in using your Google account.
For MindMup users who currently save maps to Google Drive, and organisational administrators of Google Apps/GSuite accounts, please check this page for key information you need to know, and key actions you may need to take as a result of this change.