Daylight Saving Time not considered in Outlook

[marcmetz]

Bug report

Describe the bug

We are facing the issue that Outlook (Microsoft Office 2019) is not considering the daylight saving time for Berlin/Europe.

To Reproduce

Summertime

Create an event on October 23, 2020, at 12 pm Europe / Berlin time.
Download for Outlook.
Open in Outlook. It will be inserted on October 23, 2020, at 1 pm

Wintertime

Create an event on October 28, 2020, at 12 pm Europe / Berlin time.
Download for Outlook.
Open in Outlook. It will be inserted on October 28, 2020, at 12 pm
Note: Here the daylight saving time changed from summer to winter-time.

System information

• OS: Windows
• Outlook (Microsoft Office 2019)

Additional context

Here how the .ics file looks like.

BEGIN:VCALENDAR
VERSION:2.0
BEGIN:VEVENT
URL:https://google.com
METHOD:PUBLISH
DTSTART;TZID=Europe/Berlin:20201023T120000
DTEND;TZID=Europe/Berlin:20201023T130000
SUMMARY:Demo Event
DESCRIPTION:
LOCATION:
END:VEVENT
END:VCALENDAR

[JoshReedSchramm]

@marcmetz did you ever find a solution to this. Had a customer report it today. It looks like to better handle DST the ics needs to have the VTIMEZONE data included but I don't think that's feasible in this library without adding in some sort of additional dependency that has that information.

[ryanjanelli]

@marcmetz @JoshReedSchramm I just ran into this same issue this past week. Was working with some clients in Amsterdam currently observing CEST. Anytime they would add it to their calendar, it was 1 hour ahead. 12:30pm start time would show up at 1:30pm.

[howells]

@ryanjanelli @JoshReedSchramm @marcmetz did any of you you work out how to get around this issue? VTIMEZONE is required but the format in which this is needed but the docs are impenetrable.

[ryanjanelli]

@howells @JoshReedSchramm My solution was to omit the timezone from the .ics completely. I was displaying the time correctly on my application to the attendee. I passed that time to react-add-to-calendar-hoc. I followed the first documentation example from here http://leibowitz.me/react-add-to-calendar-hoc/docs/ . This worked for my situation. I can see this not being a solution if someone wanted to share that .ics file with a colleague in a different time zone. That would cause it to display incorrectly.

[evnp]

We've been running into this issue, and have resolved it by adding VTIMEZONE components to .ics files produced by this library. We've been using https://github.com/add2cal/timezones-ical-library to build the VTIMEZONE text, which seems to work pretty well.

I forked react-add-to-calendar-hoc in order to add the ability to insert the VTIMEZONE component into the .ics file during buildShareFile. We also opened a pull request here with that functionality: #62

This is the glue code we're using to integrate these two libraries:

import { tzlib_get_ical_block, tzlib_get_timezones } from 'timezones-ical-library';

const timezone = Intl.DateTimeFormat().resolvedOptions().timeZone;
const vtimezoneOptions = tzlib_get_timezones();
let [vtimezone = null] = vtimezoneOptions.includes(timezone) ? tzlib_get_ical_block(timezone) : [];
// tzlib uses \r\n as newline characters which we don't want, replace them with \n here:
vtimezone = vtimezone?.replace(/\r\n/g, '\n');

const AddToCalendarDropdown = AddToCalendarHOC(Button, Dropdown);
return (
  <AddToCalendarDropdown event={{ timezone, vtimezone, /* ...etc... */ }} />
);