diff --git a/Netkan/Sources/Jenkins/JenkinsBuild.cs b/Netkan/Sources/Jenkins/JenkinsBuild.cs
index 61a1e3d40..53f21067c 100644
--- a/Netkan/Sources/Jenkins/JenkinsBuild.cs
+++ b/Netkan/Sources/Jenkins/JenkinsBuild.cs
@@ -30,7 +30,7 @@ public class JenkinsBuild
     public class UnixDateTimeMillisecondsConverter : DateTimeConverterBase
     {
         public override object? ReadJson(JsonReader reader, Type objectType, object? existingValue, JsonSerializer serializer)
-            => reader.Value is double d
+            => reader.Value is long d
                 ? UnixEpoch.AddMilliseconds(d)
                 : null;
 
diff --git a/Tests/NetKAN/Sources/Jenkins/JenkinsApiTests.cs b/Tests/NetKAN/Sources/Jenkins/JenkinsApiTests.cs
index 01011653f..ee7ad2a9b 100644
--- a/Tests/NetKAN/Sources/Jenkins/JenkinsApiTests.cs
+++ b/Tests/NetKAN/Sources/Jenkins/JenkinsApiTests.cs
@@ -48,6 +48,7 @@ public void GetLatestBuild_ModuleManager_Works()
             // Assert
             Assert.IsNotNull(build?.Url);
             Assert.IsNotNull(build?.Artifacts);
+            Assert.IsNotNull(build?.Timestamp);
         }
 
         private string?       _cachePath;