diff --git a/CryptoExchange.Net.UnitTests/CryptoExchange.Net.UnitTests.csproj b/CryptoExchange.Net.UnitTests/CryptoExchange.Net.UnitTests.csproj
index 28c7213..f521b29 100644
--- a/CryptoExchange.Net.UnitTests/CryptoExchange.Net.UnitTests.csproj
+++ b/CryptoExchange.Net.UnitTests/CryptoExchange.Net.UnitTests.csproj
@@ -7,10 +7,10 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <packagereference Include="Microsoft.NET.Test.Sdk" Version="15.0.0"></packagereference>
-    <PackageReference Include="Moq" Version="4.7.145" />
-    <packagereference Include="NUnit" Version="3.6.1"></packagereference>
-    <packagereference Include="NUnit3TestAdapter" Version="3.8.0-alpha1"></packagereference>
+    <packagereference Include="Microsoft.NET.Test.Sdk" Version="15.9.0-preview-20180807-05"></packagereference>
+    <PackageReference Include="Moq" Version="4.9.0" />
+    <packagereference Include="NUnit" Version="3.10.1"></packagereference>
+    <packagereference Include="NUnit3TestAdapter" Version="3.10.0"></packagereference>
   </ItemGroup>
 
   <ItemGroup>
diff --git a/CryptoExchange.Net/Converters/ArrayConverter.cs b/CryptoExchange.Net/Converters/ArrayConverter.cs
index 39d745b..d2c856f 100644
--- a/CryptoExchange.Net/Converters/ArrayConverter.cs
+++ b/CryptoExchange.Net/Converters/ArrayConverter.cs
@@ -45,7 +45,7 @@ namespace CryptoExchange.Net.Converters
 
                     if ((property.PropertyType == typeof(decimal) 
                      || property.PropertyType == typeof(decimal?))
-                     && value.ToString().Contains("e"))
+                     && (value != null && value.ToString().Contains("e")))
                     {
                         if (decimal.TryParse(value.ToString(), NumberStyles.Float, CultureInfo.InvariantCulture, out var dec))
                             property.SetValue(result, dec);