Synchronize calendars and contacts

 Vdirsyncer synchronizes your calendars and addressbooks between two storages.
 The most popular purpose is to synchronize a CalDAV/CardDAV server with a local
 folder or file. The local data can then be accessed via a variety of programs,
 none of which have to know or worry about syncing to a server.
 .
 It aims to be for CalDAV and CardDAV what OfflineIMAP is for IMAP.