When moving over to OX for email services, you should import your existing calendars so all your future & past appointments are added to your OX calendar.
See a guide here for how to import your existing calendar in to OX:
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 Import
4: Select your Calendar file. Please note that OX only supports iCal files for importing. Then select Import . Once done, you'll see your appointments in your OX Calendar.
