We know many of you have been wondering about the state of Spanning Sync and MobileMe calendars, and thought it was a good time for an update.
To recap, last Fall Apple made the switch to the new MobileMe calendar format official, but allowed users to remain with the old calendars if they chose. However, on May 5 all MobileMe calendar users will be required to switch to the new format. What's different about the new format? Previously, your calendars were stored on your computer and synced to MobileMe. With the new format, your calendars are stored in the cloud with MobileMe but apps such as iCal on the Mac and Calendar on iOS can interact with these calendars through a standard called CalDAV. The new MobileMe calendars include a better web interface, the ability to share calendars, and critically important to developers, Apple does not allow developers to sync calendars to CalDAV. Since Spanning Sync does its job using Apple's Sync Services system, the change effectively breaks Spanning Sync's ability to sync with these calendars.
Obviously, since Spanning Sync worked with MobileMe calendars before, our MobileMe customers expected it to continue to work and we wanted to accommodate them. But, in the end, we decided that Spanning Sync and MobileMe calendars aren't a good fit for each other.
1) Spanning Sync was created to sync calendars on your Mac with Google Calendar, but the new MobileMe calendars aren't on your Mac. They live in the cloud, just like Google Calendar.
2) While some of our customers are clearly using both, we don't see much benefit to using two cloud-based calendaring services whose feature sets overlap almost completely. Instead, we think users will eventually choose MobileMe calendars or Google Calendar, but not both.
3) It would take an enormous amount of resources to make Spanning Sync a full-fledged CalDAV client. Unfortunately, Apple doesn't include any libraries to help developers work with CalDAV, WebDAV, or iCalendar, which are all complex technologies and all required to make this work. It would be a lot like writing iCal from scratch, minus the UI.
So what does this mean for Spanning Sync users who also use MobileMe?
First, this change is only for MobileMe calendars. If you don't use MobileMe calendars or you don't currently use Spanning Sync to sync MobileMe calendars, then this change doesn't affect you.
Also keep in mind that there's no reason you can't put some calendars on MobileMe and keep others on your Mac for syncing to Google Calendar with Spanning Sync. For example, if you share some calendars with your family via MobileMe and others with coworkers via Google Calendar, you can still do that even with the new MobileMe calendars. In iCal, just be sure to create these calendars "On My Mac".
And if you were syncing your local calendars to MobileMe and also to Google Calendar, it might be time to examine the reasons for having both. Remember, you can access both your MobileMe and Google calendars from any web browser, and both support sharing with others.