After some testing the past week, we have confirmed this is an issue on Outlook.com. There is no way to force Outlook to refresh a calendar subscription, and for some reason it has stopped refreshing many of the Hebcal calendar feeds.

We have confirmed that if you unsubscribe from a Hebcal calendar in Outlook Web and then re-subscribe, the problem resolves itself immediately and you will see the events in Outlook.com in a matter of seconds. I hope this approach will work for you too!

G'mar Chatima Tova!

Thanks for your message.

We have confirmed that our Jewish Holidays (only major holidays) feed contains only major holidays such as Rosh Hashana, Yom Kippur, Passover, Hanukkah. That feed does NOT include minor & modern holidays, fast days or Rosh Chodesh.

We offer a separate Jewish Holidays (all holidays)  feed which contains major, minor, modern Israeli holidays, fast days and more.

You can subscribe any of these specialized feeds at https://www.hebcal.com/ical/

We note that you mention "Gedaliah Fast" and not "Tzom Gedaliah". Some non-Hebcal holiday feed providers (for example Google Calendar itself) use the event title "Gedaliah Fast". If you're seeing that event title and not "Tzom Gedaliah" then it suggests that you didn't subscribe via Hebcal.com. For the fast of Gedaliah, only use the title "Tzom Gedaliah"