I want to move my existing calendar entries from an older version of Thunderbird to a new computer where I have installed the most recent version of Thunderbird. I was able to successfully move my address book by creating an LDIF file and exporting and then importing it. Similarly, I have exported the calendar data from the older Thunderbird to an ICS file. But I can't see any way to import this ICS file into the new version of Thunderbird.