There is an external calendar subscription feature in WebLearn, but, unfortunately, it still has some limitations:
• doesn’t support full day events;
• doesn’t support events not defined with <event>;
• doesn’t support re-occurring events;
• doesn’t support events without end time
Most of these issues are limitations of the library used (ical4j) and the ical import feature from the Schedule tool.
Thanks to Nuno Fernandes for this useful information