Open X-change uses CalDav as its Calendar system, as such, it can sync across a number of applications so that you can see your up-to-date appointments on your device of choice.
You can sync your OX Calendar with Thunderbird for up-to-date appointments across the board. See this guide for how to do so:
1: In OX Webmail, click on the "3 lines" (hamburger) menu in the top left.
2: Click "Calendar"
3: Highlight the calendar you'd like to set up syncing for, select the 3 dots and in the drop-down, select Properties
4. Copy your CalDAV URL.
5. In Thunderbird, select New Calendar... in the bottom left of your Calendar section.
6. Select On the Network and then Next in the popup.
7. Now, under Location, paste in the CalDav URL. Enter your mailbox into User name: Select Find Calendars , and you'll then need to enter your password. You'll then see the Calendar in your list.
