Adventures in synchronisation volume 2 - Calendar
Synchronising calendar details across multiple devices introduces some additional complications beyond the requirement of static data such as contact details.
My primary electronic calendar is the Lightning add-on for the Thunderbird  email client on my Windows PC. I'm not a big calendar user, but it would be nice to have access to this information from other devices and locations, in particular the default Calendar application on an Android tablet.
In particular, I need:
- Meeting invitations to come from my normal email address, not a gmail.com or outlook.com address. Using multiple email addresses is unnecessarily confusing for clients and colleagues.
- Attendance responses (where invitees accept or reject the meeting)
- The calendar should be a 'normal' part of my everyday email/calendar process.
Web-based calendars, such as Google Calendar , Microsoft Live  and similar could be an option, but have some issues with email addresses and compatibility with my desktop calendar. An in any case, I'm not all that happy about relying on a third party service for private data (but millions of other people are relaxed about it, so it's probably just me...).
Following my good experience with ownCloud  as a synchronisation platform for address books, I've been experimenting with the calendar support and things are looking good.
What works well
Events added and maintained from my desktop calendar are synchronised to the Android tablet calendar. This includes event reminders, repeating events and attendance responses.
Because the calendar information is privately hosted, and only accessible with an SSL secured connection, I'm reasonably happy that it's secure. At least secure enough to use for a calendar...
Because the ownCloud interface uses the CalDAV standard , there are options for synchronisation with other applications including Microsoft Outlook which reportedly work well, but I haven't tried them myself.
What works a bit less well
The Android view of the calendar process seems to have some issues:
- Event invitations don't get sent from the calendar application, although the invitees are recorded and synchronised to the desktop calendar, from where the invites can be sent. This issue seems common to non-google calendars.
- Attendance responses don't get processed. The email application doesn't recognise the VCALENDAR/VEVENT content of the response email.
- Editing a repeating event on Android can create extra occurrences inappropriately.
I can accept these limitations.
Tasks and Notes
As well as normal calendar events, the webDAV/calDAV protocols also allows for task (VTASK) and note (VJOURNAL) storage. How well these actually synchronise between devices is a bit more variable. In particular, the concept of notes is not widely supported by calendaring applications.
I wonder what else I can do with ownCloud?
 Lightning add-on for Thunderbird
 Google calendar
 Outlook.com part of the Microsoft Live offering
 ownCloud project
 CalDAV wikipedia article
 Davdroid android app - use at least version 0.4.4 to get the right email account associated with the calendar.
I don't endorse or recommend any particular software package or solution, this article describes what worked for me, but you should make your own assessments before installing or using any of these programs.