You can sync your Arosoftware Calendar with Thunderbird Calendar

Add a Calendar account to thunderbird

1. Start by locating your "My Caldav URL"
   
2. Open Thunderbird
   
3. Click on the "File" menu followed by "New" followed by "Calendar"
   
4. Select the "On the Network" option
   
5. Select the "CalDAV" option for the "Format" field
   
6. Enter your "My Caldav URL" into the "Location" field
   
7. Click "Continue"
   
8. Give the Calendar a name such as "My Arosoftware Calendar"
   
9. Set the colour for events within this Calendar
   
10. Click "Continue"
    
11. Your Arosoftware calendar account has now been added