diff --git a/ln.build/semver/SemVersion.cs b/ln.build/semver/SemVersion.cs
index 2a4e591..9464d96 100644
--- a/ln.build/semver/SemVersion.cs
+++ b/ln.build/semver/SemVersion.cs
@@ -2,8 +2,10 @@
 
 using System;
 using System.IO;
+using System.Runtime.InteropServices.ComTypes;
 using System.Text;
 using System.Text.RegularExpressions;
+using Jint.Parser.Ast;
 using ln.build.semver;
 using Microsoft.VisualBasic;
 
@@ -81,6 +83,9 @@ namespace ln.build.semver
 
         public static bool operator <(SemVersion a,SemVersion b)
         {
+            if (a is null || b is null)
+                return false;
+
             if (a.Major < b.Major)
                 return true;
             if (a.Major > b.Major)
@@ -108,6 +113,9 @@ namespace ln.build.semver
         }
         public static bool operator >(SemVersion b,SemVersion a)
         {
+            if (a is null || b is null)
+                return false;
+
             if (a.Major < b.Major)
                 return true;
             if (a.Major > b.Major)