diff --git a/src/Sonarr.Api.V3/Calendar/CalendarFeedController.cs b/src/Sonarr.Api.V3/Calendar/CalendarFeedController.cs
index fcd8208d0..b7cdc43f3 100644
--- a/src/Sonarr.Api.V3/Calendar/CalendarFeedController.cs
+++ b/src/Sonarr.Api.V3/Calendar/CalendarFeedController.cs
@@ -77,12 +77,12 @@ public IActionResult GetCalendarFeed(int pastDays = 7, int futureDays = 28, stri
 
                 if (asAllDay)
                 {
-                    occurrence.Start = new CalDateTime(episode.AirDateUtc.Value.ToLocalTime()) { HasTime = false };
+                    occurrence.Start = new CalDateTime(episode.AirDateUtc.Value.ToLocalTime(), false);
                 }
                 else
                 {
-                    occurrence.Start = new CalDateTime(episode.AirDateUtc.Value) { HasTime = true };
-                    occurrence.End = new CalDateTime(episode.AirDateUtc.Value.AddMinutes(series.Runtime)) { HasTime = true };
+                    occurrence.Start = new CalDateTime(episode.AirDateUtc.Value, true);
+                    occurrence.End = new CalDateTime(episode.AirDateUtc.Value.AddMinutes(series.Runtime), true);
                 }
 
                 switch (series.SeriesType)
@@ -96,10 +96,10 @@ public IActionResult GetCalendarFeed(int pastDays = 7, int futureDays = 28, stri
                 }
             }
 
-            var serializer = (IStringSerializer)new SerializerFactory().Build(calendar.GetType(), new SerializationContext());
-            var icalendar = serializer.SerializeToString(calendar);
+            var serializer = new SerializerFactory().Build(calendar.GetType(), new SerializationContext()) as IStringSerializer;
+            var icalendar = serializer?.SerializeToString(calendar);
 
-            return Content(icalendar, "text/calendar");
+            return icalendar is null ? NoContent() : Content(icalendar, "text/calendar");
         }
     }
 }
diff --git a/src/Sonarr.Api.V3/Sonarr.Api.V3.csproj b/src/Sonarr.Api.V3/Sonarr.Api.V3.csproj
index 020e9cdff..7b95108f6 100644
--- a/src/Sonarr.Api.V3/Sonarr.Api.V3.csproj
+++ b/src/Sonarr.Api.V3/Sonarr.Api.V3.csproj
@@ -4,7 +4,7 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="FluentValidation" Version="9.5.4" />
-    <PackageReference Include="Ical.Net" Version="4.3.1" />
+    <PackageReference Include="Ical.Net" Version="5.2.1" />
     <PackageReference Include="NLog" Version="5.5.1" />
     <PackageReference Include="Swashbuckle.AspNetCore.Annotations" Version="10.1.7" />
   </ItemGroup>
diff --git a/src/Sonarr.Api.V5/Calendar/CalendarFeedController.cs b/src/Sonarr.Api.V5/Calendar/CalendarFeedController.cs
index c8c0b4095..ed11365a6 100644
--- a/src/Sonarr.Api.V5/Calendar/CalendarFeedController.cs
+++ b/src/Sonarr.Api.V5/Calendar/CalendarFeedController.cs
@@ -27,7 +27,7 @@ public CalendarFeedController(IEpisodeService episodeService, ISeriesService ser
     }
 
     [HttpGet("Sonarr.ics")]
-    public ContentHttpResult GetCalendarFeed(int pastDays = 7, int futureDays = 28, string tags = "", bool unmonitored = false, bool premieresOnly = false, bool asAllDay = false, bool includeSpecials = true)
+    public Results<ContentHttpResult, NoContent> GetCalendarFeed(int pastDays = 7, int futureDays = 28, string tags = "", bool unmonitored = false, bool premieresOnly = false, bool asAllDay = false, bool includeSpecials = true)
     {
         var start = DateTime.Today.AddDays(-pastDays);
         var end = DateTime.Today.AddDays(futureDays);
@@ -76,12 +76,12 @@ public ContentHttpResult GetCalendarFeed(int pastDays = 7, int futureDays = 28,
 
             if (asAllDay)
             {
-                occurrence.Start = new CalDateTime(episode.AirDateUtc!.Value.ToLocalTime()) { HasTime = false };
+                occurrence.Start = new CalDateTime(episode.AirDateUtc!.Value.ToLocalTime(), false);
             }
             else
             {
-                occurrence.Start = new CalDateTime(episode.AirDateUtc!.Value) { HasTime = true };
-                occurrence.End = new CalDateTime(episode.AirDateUtc.Value.AddMinutes(series.Runtime)) { HasTime = true };
+                occurrence.Start = new CalDateTime(episode.AirDateUtc!.Value, true);
+                occurrence.End = new CalDateTime(episode.AirDateUtc.Value.AddMinutes(series.Runtime), true);
             }
 
             switch (series.SeriesType)
@@ -95,9 +95,9 @@ public ContentHttpResult GetCalendarFeed(int pastDays = 7, int futureDays = 28,
             }
         }
 
-        var serializer = (IStringSerializer)new SerializerFactory().Build(calendar.GetType(), new SerializationContext());
-        var icalendar = serializer.SerializeToString(calendar);
+        var serializer = new SerializerFactory().Build(calendar.GetType(), new SerializationContext()) as IStringSerializer;
+        var icalendar = serializer?.SerializeToString(calendar);
 
-        return TypedResults.Content(icalendar, "text/calendar");
+        return icalendar is null ? TypedResults.NoContent() : TypedResults.Content(icalendar, "text/calendar");
     }
 }
diff --git a/src/Sonarr.Api.V5/Sonarr.Api.V5.csproj b/src/Sonarr.Api.V5/Sonarr.Api.V5.csproj
index 9e67c56e1..0b7a7df98 100644
--- a/src/Sonarr.Api.V5/Sonarr.Api.V5.csproj
+++ b/src/Sonarr.Api.V5/Sonarr.Api.V5.csproj
@@ -7,7 +7,7 @@
 	</PropertyGroup>
 	<ItemGroup>
 		<PackageReference Include="FluentValidation" Version="9.5.4" />
-		<PackageReference Include="Ical.Net" Version="4.3.1" />
+		<PackageReference Include="Ical.Net" Version="5.2.1" />
 		<PackageReference Include="NLog" Version="5.5.1" />
 		<PackageReference Include="Swashbuckle.AspNetCore.Annotations" Version="10.1.7" />
 	</ItemGroup>