Access other Users Mailboxes via API

[Valerion]

If you use http://servername/api/dav you can access a mailbox via the WebDAV interface. CalDAV allows you to read and write appointments here, though the corresponding Free/Busy entries are not always updated correctly. This is slated to eventually replace the API you are using at the moment.

I'm not entirely sure if you can access other users' stores through this yet, unfortunately.