diff --git a/src/NmeaParser/Nmea/NmeaMessage.cs b/src/NmeaParser/Nmea/NmeaMessage.cs
index 4e2bbf9..4f939b9 100644
--- a/src/NmeaParser/Nmea/NmeaMessage.cs
+++ b/src/NmeaParser/Nmea/NmeaMessage.cs
@@ -301,7 +301,7 @@ namespace NmeaParser.Messages
         /// </summary>
         /// <remarks>
         /// This value is deduced from <c>System.Diagnostics.Stopwatch.GetTimestamp() * 1000d / System.Diagnostics.Stopwatch.Frequency</c>.
-        /// You can use it to calculate the age of the message in seconds by calculating the difference between the timestamp and the above expression
+        /// You can use it to calculate the age of the message in milliseconds by calculating the difference between the timestamp and the above expression
         /// </remarks>
         public double Timestamp { get; }
     }
diff --git a/src/SampleApp.WinDesktop/UnknownMessageControl.xaml.cs b/src/SampleApp.WinDesktop/UnknownMessageControl.xaml.cs
index af54a6e..d609a9e 100644
--- a/src/SampleApp.WinDesktop/UnknownMessageControl.xaml.cs
+++ b/src/SampleApp.WinDesktop/UnknownMessageControl.xaml.cs
@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Windows;
 using System.Windows.Controls;
@@ -48,7 +49,7 @@ namespace SampleApp.WinDesktop
                 List<string> values = new List<string>();
                 foreach (var prop in props.OrderBy(t => t.Name))
                 {
-                    if (prop.Name == nameof(NmeaMessage.MessageType) || prop.Name == nameof(NmeaMessage.Checksum))
+                    if (prop.Name == nameof(NmeaMessage.MessageType) || prop.Name == nameof(NmeaMessage.Checksum) || prop.Name == nameof(NmeaMessage.Timestamp))
                         continue;
                     var value = prop.GetValue(e.NewValue);
                     if (!(value is string) && value is System.Collections.IEnumerable arr)
@@ -60,6 +61,13 @@ namespace SampleApp.WinDesktop
                     }
                     values.Add($"{prop.Name}: {value}");
                 }
+                if (e.NewValue is NmeaMessage msg)
+                {
+                    var age = (System.Diagnostics.Stopwatch.GetTimestamp() * 1000d / System.Diagnostics.Stopwatch.Frequency) - msg.Timestamp;
+                    values.Add($"Timestamp: " + DateTime.Now.AddMilliseconds(-age).TimeOfDay.ToString("h\\:mm\\:ss"));
+                }
+                //;
+
                 ctrl.Values.ItemsSource = values;
             }
         }
diff --git a/src/UnitTests/NmeaParser.Tests.NET/NmeaParser.Tests.Net.csproj b/src/UnitTests/NmeaParser.Tests.NET/NmeaParser.Tests.Net.csproj
index 7c7832d..f5561d2 100644
--- a/src/UnitTests/NmeaParser.Tests.NET/NmeaParser.Tests.Net.csproj
+++ b/src/UnitTests/NmeaParser.Tests.NET/NmeaParser.Tests.Net.csproj
@@ -3,6 +3,7 @@
   <PropertyGroup>
     <TargetFrameworks>net451;netcoreapp3.1</TargetFrameworks>
     <IsPackable>false</IsPackable>
+    <LangVersion>8.0</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>