Investigating the needed software, state of affairs is:
Android Calendar and Contact Sync is possible via ActiveSync. There is a open source replacement for ActiveSync which claims to be compatible, which is z-push.
Overview of Active Sync enabled Linux Software:
Nice to have would be:
-easy install and setup – one package, no separate config of database or external programs needed
–Kolab Groupware, claims to have ActiveSync
Norway – good speeds from the middle or Europe to Norway. Norwegian people rejected data retention some time ago. Good location for a proxy/web-out vpn endpoint.
Seafile – can sync multiple folders, contrary to dropbox. Community Edition is somewhat fiddlish to configure, consider using the Pro edition which is free but limited to some users
Owncloud – seems to have CalDAV Calender sync support, according to Seafile forum lacks synch speed