Looks like an issue with you using an older version of Node.js

Try using @hebcal/core version 5.3.3 and see if that fixes the problem for you?

https://github.com/hebcal/hebcal-es6/releases/tag/v5.3.3

This article describes how to make changes to a Yahrzeit + Anniversary calendar that you downloaded, exported or subscribed to in a calendar app like Outlook, Google Calendar / Android, or Apple (iOS, iPhone, iPad or Mac). 

https://www.hebcal.com/home/632/how-to-make-changes-to-a-yahrzeit-anniversary-calendar

These instructions apply to personal events such as yahrzeits, Hebrew Birthdays, and Hebrew Anniversaries.

Hi, thanks for contacting Hebcal. Although the underlying Hebcal algorithms support calculation of halachic times (zmanim) we have not built a website interface for calculating times. We do plan to eventually offer this feature but do not have a fi date to share.

We do have an experimental zmanim feed which requires some technical comfort editing a URL and offers only very limited customization options

https://www.hebcal.com/home/4522/zmanim-icalendar-feed

Consider MyZmanim.com as an alternative website that offers lots of customization

Thanks for your question. The Jewish new year, Rosh Hashanah, occurs in the autumn. The year changes from 5784 to 5785 on Wednesday 2 October 2024.

For more information read the Wikipedia article describing the 4 new years in the Hebrew calendar

https://en.m.wikipedia.org/wiki/Rosh_Hashanah#The_Four_%22New_Years%22

Yes, that should work!

Are you building your app in JavaScript? There is a great API that estimates timeZoneID from latitude and longitude

https://www.npmjs.com/package/geo-tz

The same API may be available in other programming languages

Thanks for using Hebcal!

Shabbat times can indeed be downloaded to iCalendar but we could improve our user experience to make this easier to find.

From a Shabbat times page like this one:

https://www.hebcal.com/shabbat?zip=02906&ue=on&M=on&lg=s

If you click the "2024 calendar" button like below:

Which will take you to a page that lets you download/subscribe as follows:

Thanks for the feedback about our Apple Watch app. We will consider this suggestion and hope to incorporate it in a future update.

Thanks for posting the screenshot. That indeed looks like it may be a pre-August 2020 subscription. You can confirm this by checking the calendar subscription details and examining the URL.

On iOS, open Calendar. Tap Calendars > the Info button ⓘ > Subscription Details

In the "Subscribed To" section, you will see a URL that contains download.hebcal.com (see screenshot below)

If the URL begins with download.hebcal.com/export/... or it begins with download.hebcal.com/v2/y/... then it is from before August 2020 and the calendar feed cannot be edited.

If the URL starts with download.hebcal.com/v3/... then it is from after August 2020 and should be editable.

Thanks for using the Hebcal Yahrzeit + Anniversary Calendar. We're sorry to hear that you're having difficulty editing an existing calendar. Our sincere apologies for the inconvenience.

This situation arises when you use a different web browser or device to visit hebcal.com from the device or browser you used to create your personal yahrzeit calendar. The calendar ID is stored in a web browser cookie, a small file placed on your device. Cookies are not transferred when you switch web browsers (for example, from Chrome to Firefox) or when you switch devices (for example, you first visited hebcal.com from a computer, then later visit from a mobile phone).

If you have a yahrzeit calendar feed in iCal (as you describe above), it should be possible to recover and edit your yahrzeit calendar using option 1 ("I have a Hebcal calendar feed subscription") described on this web page:

https://www.hebcal.com/home/632/how-to-make-changes-to-a-yahrzeit-anniversary-calendar

Please let us know if this helps!