Apple has released OS X 10.9 Mavericks. If you are running BusyCal or BusySync, please read the following information.
Sync Services is no longer supported on Mavericks
One of the biggest changes in Mavericks is the removal of Sync Services, an underlying framework on OS X used for syncing local calendars with OS X Calendar.
This change affects any third-party app that syncs with OS X Calendar via Sync Services, including BusyCal 1.6 and BusySync 2.3. This change does not affect BusyCal 2.5 as it does not sync with Sync Services.
BusyCal 2.5 is fully compatible with Mavericks
BusyCal 2.5 is fully compatible with Mavericks. If you're running BusyCal 2.5, you can safely upgrade to Mavericks and ignore the rest of this document.
BusyCal 1.6 is not compatible with Mavericks
BusyCal 1.6 is not compatible with Mavericks, as it requires Sync Services for syncing local calendars with OS X Calendar. BusyCal 1.6 may work on Mavericks if you are syncing exclusively with iCloud or Google, but we do not support running BusyCal 1.6 on Mavericks.
Mac OS X, iCloud and Google are constantly changing. Apps that sync with them must be continually updated to maintain compatibility. BusyCal 1.6 is no longer being updated and we do not support running it on Mavericks. We recommend upgrading to BusyCal 2.5, which is under active development.
For more info, see BusyCal 1.6 Mavericks compatibility.
BusySync 2.3 is not compatible with Mavericks
BusySync 2.3 is not compatible with Mavericks, as it requires Sync Services for syncing with OS X Calendar. If you upgrade to Mavericks, you will have to discontinue using BusySync. We recommend migrating to a cloud-based service like iCloud, Google or Exchange and upgrading to BusyCal 2.5.
For more info, see BusySync 2.3 Mavericks compatibility.
Upgrade to BusyCal 2.5
If you upgrade to Mavericks and are currently running BusyCal 1.6 or BusySync 2.3, we highly recommend that you upgrade to BusyCal 2.5. BusyCal 2.5 is fully compatible with Mavericks, iCloud, Google and Exchange and includes a ton of great features. For more info see Upgrading to BusyCal 2.5.