iCal - all day events lasting one day are recognized for the day before

[DFS-90]

Hello,

I got a weird problem concerning the ICS calendar platform and all day events that last one single day. I managed to connect my Kopano calendar to HomeAssistant via SSL (Let’s encrypt).

Everything else works fine:

• umlauts
• all day events that last two or more days
• events that last a certain period of time, e. g. 8 am to 7 pm

As soon as I create an all day event that lasts one day, it is recognized for the day before.

Example:

• event is created for 2022/09/11, all day
• my mobile phone recognizes that event for 2022/09/11, all day
• Kopano WebApp recognizes that event for 2022/09/11, all day
• HomeAssistant recognizes that event for 2022/09/10, all day

This is an excerpt from the .ics-file:

BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Kopano//11.0.2//EN CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VEVENT TRANSP:TRANSPARENT X-MICROSOFT-CDO-INTENDEDSTATUS:FREE CREATED:20220907T230853Z LAST-MODIFIED:20220907T230901Z DTSTAMP:20220907T230901Z DTSTART;VALUE=DATE:20220910 DTEND;VALUE=DATE:20220911 SUMMARY:Test WebApp ganztägig 11.09. PRIORITY:5 CLASS:PUBLIC UID: 040000008200E00074C5B7101A82E008000000008064F3D00EC3D801000000000000000001 000000C5EA678954DE4A9D840365DFBE14C377 X-MICROSOFT-CDO-OWNER-CRITICAL-CHANGE:20220908T075343Z X-MICROSOFT-CDO-ATTENDEE-CRITICAL-CHANGE:20220908T075343Z X-MICROSOFT-CDO-APPT-SEQUENCE:0 X-MICROSOFT-CDO-OWNERAPPTID:-1 X-MICROSOFT-CDO-ALLDAYEVENT:TRUE END:VEVENT

I also did a second test with an empty calendar for 2022-09-12 to be sure:

BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Kopano//11.0.2//EN CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VEVENT TRANSP:TRANSPARENT X-MICROSOFT-CDO-INTENDEDSTATUS:FREE CREATED:20220908T213511Z LAST-MODIFIED:20220908T213511Z DTSTAMP:20220908T213511Z DTSTART;VALUE=DATE:20220911 DTEND;VALUE=DATE:20220912 SUMMARY:appointment test 2022-09-12, all day PRIORITY:5 CLASS:PUBLIC UID: 040000008200E00074C5B7101A82E00800000000800564E4CAC3D801000000000000000001 00000035A1B8102AFD4AE9AC9D0C575AFC4F57 X-MICROSOFT-CDO-OWNER-CRITICAL-CHANGE:20220908T213519Z X-MICROSOFT-CDO-ATTENDEE-CRITICAL-CHANGE:20220908T213519Z X-MICROSOFT-CDO-APPT-SEQUENCE:0 X-MICROSOFT-CDO-OWNERAPPTID:-1 X-MICROSOFT-CDO-ALLDAYEVENT:TRUE END:VEVENT END:VCALENDAR

The issue happened when trying to connect my Kopano calendar to HomeAssistant (please also see HomeAssistant community).

I’ve also tried to switch to kDAV instead of Kopano iCal - same behaviour. All timezones are set correctly (“Europe/Berlin”).

Does anybody know how to troubleshoot this?

Thanks in advance, David