ich habe nämlich dem support geschrieben:

I am a big fan of busycal and busy contact both but I must say the update to V3 is quite over priced and I won’t go for it. Unfortunately it has erased my V2 app. How can I come back to it?

You can revert from BusyCal 3 to BusyCal 2 as follows:

1. Launch BusyCal 3 while holding down the option key to display the Startup Options dialog, then select Reset BusyCal and click Continue. Resetting BusyCal will disconnect from all servers (your data will remain on the servers), delete the BusyCal database, and quit.

2. Download and run the BusyCal 2 installer.

http://www.busymac.com/download/bcl-2.6.9.zip

3. Launch BusyCal 2 and go through the setup assistant. Make sure you do not import the local calendars from OS X Calendar as they will be out-of-date.

4. If BusyCal does not automatically connect to your iCloud, Google or Exchange accounts, you may connect to them manually in BusyCal > Preferences > Accounts.