ha-calendar-fixes.patch

diff --git a/custom_components/calendar_export/api.py b/custom_components/calendar_export/api.py
index e42a23c..21a941d 100644
--- a/custom_components/calendar_export/api.py
+++ b/custom_components/calendar_export/api.py
@@ -1,6 +1,7 @@
 """API for calendar export."""
 
 from datetime import datetime, timedelta
+from hashlib import sha256
 from http import HTTPStatus
 
 import pytz
@@ -17,6 +18,13 @@ from homeassistant.components.todo import (
 from icalendar import Calendar, Event, Todo
 
 
+def uid(*args):
+    m = sha256()
+    for arg in args:
+        m.update(str(arg).encode())
+    return m.hexdigest()
+
+
 class CalendarExportAPI(http.HomeAssistantView):
     """View to export calendar in ICS format."""
 
@@ -38,6 +46,7 @@ class CalendarExportAPI(http.HomeAssistantView):
 
         # Generate ICS data
         cal = Calendar()
+        cal["VERSION"] = "2.0" # RFC5545 3.7.4
         cal["X-WR-CALNAME"] = entity.name
         cal["PRODID"] = "-//Home Assistant//Calendar Export//EN"
 
@@ -51,8 +60,9 @@ class CalendarExportAPI(http.HomeAssistantView):
 
         for event in events:
             e = Event()
-            e.add("uid", event.uid)
+            e.add("uid", uid(event.uid, event.start))
             e.add("summary", event.summary)
+            e.add("dtstamp", datetime(1970, 1, 1))
             e.add("dtstart", event.start)
             e.add("dtend", event.end)
             if event.description: