docs/ics_format.txt

@@ -3,10 +3,16 @@ ICS files from Microsoft Outlook differ from those that were created by Gnome Ev
 
 Evolution
 ---------
+all line endings are \r\n
+
 all day event:
 DTSTART;VALUE=DATE:20230908
 DTEND;VALUE=DATE:20230909
 
+an all day event can span over multiple days and look like this:
+DTSTART;VALUE=DATE:20230911^M$
+DTEND;VALUE=DATE:20230916^M$
+
 appointment:
 DTSTART;TZID=/freeassociation.sourceforge.net/Continent/City:
  20230909T090000