Backup
- In Week Calendar go to Calendars and select only the calendar(s) you want to export
- Now, press Tools > Share & Print
- Press Export Select the period you want Press Export
- Email the file to yourself
Please note so called "rolling" events cannot be exported to an ICS file.
Restore
- Open the email you sent to yourself
- Press the ICS file
- Select Add All at top right
- You'll be asked to select a calendar to import events in