Online meeting URL should be stored in LOCATION property for CalDAV interoperability

Feature request
1

When creating a calendar event in eM Client with a Nextcloud Talk online meeting, the meeting URL is stored in DESCRIPTION, X-ALT-DESC, and X-MAILCLIENT-ONLINE-MEETING, but not in the standard LOCATION property.

This breaks interoperability with Nextcloud Talk, which relies on the LOCATION field to detect upcoming meetings and display them on its dashboard (per RFC 5545 Section 3.8.1.7).

What eM Client currently produces:

SUMMARY:test talk
DESCRIPTION:Online aan deze meeting deelnemen op https://cloud.example.com/index.php/call/wtx4skp4\n\nVergadering-ID: wtx4skp4
X-ALT-DESC;FMTTYPE=text/html:Online aan deze meeting deelnemen op <a href="https://cloud.example.com/index.php/call/wtx4skp4">...</a>
X-MAILCLIENT-ONLINE-MEETING:https://cloud.example.com/index.php/call/wtx4skp4

Note: no LOCATION property is present.

What is expected:

LOCATION:https://cloud.example.com/index.php/call/wtx4skp4
DESCRIPTION:...
X-ALT-DESC;FMTTYPE=text/html:...
X-MAILCLIENT-ONLINE-MEETING:https://cloud.example.com/index.php/call/wtx4skp4

The online meeting URL should also be written to the LOCATION property. This is how the Nextcloud Calendar app handles it, and it is consistent with how other CalDAV clients store online meeting locations.

Why this matters:

Nextcloud Talk searches the LOCATION property for /call/ to identify events linked to a Talk conversation. Without it, meetings created in eM Client never appear on the Talk start screen under “Schedule meetings”, even though the meeting link is present in other fields.

This likely affects all online meeting providers, not just Nextcloud Talk — any server-side integration that reads the standard LOCATION property to find meeting URLs will fail.

Steps to reproduce:

  1. Connect eM Client to a Nextcloud instance via CalDAV
  2. Create a calendar event and add a Nextcloud Talk meeting
  3. Export or inspect the raw ICS data — LOCATION is missing
  4. Open Nextcloud Talk in a browser — the meeting does not appear under “Schedule meetings”
  5. Create the same event via Nextcloud Calendar — LOCATION is set and the meeting appears correctly

Environment: eM Client 10.4 (build 4293), Nextcloud 32/33 with Talk 23

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