Remote Calendar chokes on X-Link entry

[wrichter]

The problem

HA no longer loads the calendar https://zuse.classyplan.app/export.php?type=ics&p=1&c=1744223054405

What version of Home Assistant Core has the issue?

core-2025.6.0

What was the last working version of Home Assistant Core?

core-2025.5.3

What type of installation are you running?

Home Assistant OS

Integration causing the issue

Remote Calendar

Link to integration documentation on our website

https://www.home-assistant.io/integrations/remote_calendar

Diagnostics information

No response

Example YAML snippet

Anything in the logs that might be useful for us?

2025-06-13 09:02:08.400 INFO (SyncWorker_6) [homeassistant.loader] Loaded remote_calendar from homeassistant.components.remote_calendar
2025-06-13 09:02:13.592 ERROR (MainThread) [homeassistant.components.remote_calendar.ics] Error parsing calendar information: Failed to parse calendar contents
2025-06-13 09:02:13.592 DEBUG (MainThread) [homeassistant.components.remote_calendar.ics] Additional calendar error detail: Invalid property name 'X-Link'

Additional information

No response

[home-assistant]

Hey there @Thomas55555, mind taking a look at this issue as it has been labeled with an integration (remote_calendar) you are listed as a code owner for? Thanks!

Code owner commands

Code owners of remote_calendar can trigger bot actions by commenting:

• @home-assistant close Closes the issue.
• @home-assistant rename Awesome new title Renames the issue.
• @home-assistant reopen Reopen the issue.
• @home-assistant unassign remote_calendar Removes the current integration label and assignees on the issue, add the integration domain after the command.
• @home-assistant add-label needs-more-information Add a label (needs-more-information, problem in dependency, problem in custom component) to the issue.
• @home-assistant remove-label needs-more-information Remove a label (needs-more-information, problem in dependency, problem in custom component) on the issue.

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[github-actions]

🔍 Potential duplicate detection

I've analyzed similar issues and found the following potential duplicates:

• #146173: Error parsing calendar in 2025.6

What to do next:

1. Please review these issues to see if they match your issue
2. If you find an existing issue that covers your problem:
   • Consider closing this issue
   • Add your findings or 👍 on the existing issue instead
3. If your issue is different or adds new aspects, please clarify how it differs

This helps keep our issues organized and ensures similar issues are consolidated for better visibility.

This message was generated automatically by our duplicate detection system.

[wrichter]

The linked issue #146173 is against the beta and is marked closed. It COULD be the same core issue (X-Link header containing lowercase characters), the calendar source seems to be valid though: https://icalendar.org/validator.html?url=https://zuse.classyplan.app/export.php?type=ics&p=1&c=1744223054405

When is the fix landing in home assistant / how can I test the fix?

[allenporter]

Re-opening #146173 and marking as a duplicate since the original issue was not yet fixed