diff --git a/src/GregClient/Requests/PackageUploadRequestBody.cs b/src/GregClient/Requests/PackageUploadRequestBody.cs
index 5e4d3c5..db12dc5 100644
--- a/src/GregClient/Requests/PackageUploadRequestBody.cs
+++ b/src/GregClient/Requests/PackageUploadRequestBody.cs
@@ -16,12 +16,13 @@ public PackageUploadRequestBody(string name, string version, string description,
         string metadata, string group, IEnumerable<PackageDependency> dependencies,
         string siteUrl, string repositoryUrl, bool containsBinaries,
         IEnumerable<string> nodeLibraryNames, IEnumerable<string> hostDependencies,
-        string copyright_holder, string copyright_year, string releaseNotesUrl)
+        string copyright_holder, string copyright_year, string releaseNotesUrl, IEnumerable<PackageCompatibility> compatibilityMatrix)
         {
             this.host_dependencies = hostDependencies;
             this.copyright_holder = copyright_holder;
             this.copyright_year = copyright_year;
             this.release_notes_url = releaseNotesUrl;
+            this.compatibility_matrix = compatibilityMatrix;
 
             this.name = name;
             this.version = version;
diff --git a/src/GregClient/Requests/PackageVersionUpload.cs b/src/GregClient/Requests/PackageVersionUpload.cs
index ad5f4b6..cda922b 100644
--- a/src/GregClient/Requests/PackageVersionUpload.cs
+++ b/src/GregClient/Requests/PackageVersionUpload.cs
@@ -79,4 +79,18 @@ public PackageDependency(string name, string version)
         public string name { get; set; }
         public string version { get; set; }
     }
+    public class PackageCompatibility
+    {
+        public PackageCompatibility(string name, List<string> versions, string min, string max)
+        {
+            this.name = name;
+            this.versions = versions;
+            this.min = min;
+            this.max = max;
+        }
+        public string name { get; set; }
+        public List<string> versions { get; set; }
+        public string min { get; set; }
+        public string max { get; set; }
+    }
 }
diff --git a/src/GregClient/Requests/PackageVersionUploadRequestBody.cs b/src/GregClient/Requests/PackageVersionUploadRequestBody.cs
index 675182c..51e5af5 100644
--- a/src/GregClient/Requests/PackageVersionUploadRequestBody.cs
+++ b/src/GregClient/Requests/PackageVersionUploadRequestBody.cs
@@ -38,7 +38,7 @@ public PackageVersionUploadRequestBody(string name, string version, string descr
           string metadata, string group, IEnumerable<PackageDependency> dependencies,
           string siteUrl, string repositoryUrl, bool containsBinaries,
           IEnumerable<string> nodeLibraryNames, IEnumerable<string> hostDependencies,
-          string copyright_holder, string copyright_year, string compatibility_matrix, string releaseNotesUrl)
+          string copyright_holder, string copyright_year, IEnumerable<PackageCompatibility> compatibilityMatrix, string releaseNotesUrl)
 
         {
             this.host_dependencies = hostDependencies;
@@ -60,6 +60,7 @@ public PackageVersionUploadRequestBody(string name, string version, string descr
             this.node_libraries = nodeLibraryNames;
             this.compatibility_matrix = compatibility_matrix;
             this.release_notes_url = releaseNotesUrl;
+            this.compatibility_matrix = compatibilityMatrix;
         }
 
         /// <summary>
@@ -132,7 +133,7 @@ public PackageVersionUploadRequestBody(string name, string version, string descr
         public IEnumerable<string> node_libraries { get; set; }
         public string copyright_holder { get; set; }
         public string copyright_year { get; set; }
-        public string compatibility_matrix { get; set; }
+        public IEnumerable<PackageCompatibility> compatibility_matrix { get; set; }
         public string release_notes_url { get; set; }
     }
 }
\ No newline at end of file
diff --git a/src/GregClient/Responses/Responses.cs b/src/GregClient/Responses/Responses.cs
index 0f88309..c5baf26 100644
--- a/src/GregClient/Responses/Responses.cs
+++ b/src/GregClient/Responses/Responses.cs
@@ -3,7 +3,6 @@
 using RestSharp;
 using Greg.Converters;
 using System.Text.Json;
-using System.Text.Json.Serialization;
 
 namespace Greg.Responses
 {
@@ -78,6 +77,13 @@ public class Dependency
 
         public string _id { get; set; }
     }
+    public class Compatibility
+    {
+        public string name { get; set; }
+        public List<string> versions { get; set; }
+        public string min { get; set; }
+        public string max { get; set; }
+    }
 
     public class PackageVersion
     {
@@ -125,6 +131,7 @@ public class PackageVersion
 
         public string size { get; set; }
         public string release_notes_url { get; set; }
+        public List<Compatibility> compatibility_matrix { get; set; }
     }
 
     public class User
diff --git a/src/GregClientTests/GregClientTests.cs b/src/GregClientTests/GregClientTests.cs
index e3da1b5..1ce0066 100644
--- a/src/GregClientTests/GregClientTests.cs
+++ b/src/GregClientTests/GregClientTests.cs
@@ -56,11 +56,11 @@ public void UploadDynamoPackageVersionTest()
             var keywords = new List<string>() { "neat", "ok" };
             var nv = new PackageVersionUploadRequestBody("Third .NET Package", "2.1.0", "", keywords, "contents", "dynamo", "0.1.0", "metadata", "group",
                             new List<PackageDependency>() { new PackageDependency("peter", "0.1.0"), new PackageDependency("stephen", "0.1.0") }, "", "",
-                            false, new List<String>(), new List<String>(), "Dynamo Team", "2021","","");
+                            false, new List<String>(), new List<String>(), "Dynamo Team", "2021",null,"");
 
             var files = new List<string>() { "../test/pedro.dyf", "../test/RootNode.dyf" };
             var request = new PackageVersionUpload(nv, files);
-            Assert.That(request.RequestBody.AsJson().Equals("{\"file_hash\":null,\"name\":\"Third .NET Package\",\"version\":\"2.1.0\",\"description\":\"\",\"group\":\"group\",\"keywords\":[\"neat\",\"ok\"],\"dependencies\":[{\"name\":\"peter\",\"version\":\"0.1.0\"},{\"name\":\"stephen\",\"version\":\"0.1.0\"}],\"host_dependencies\":[],\"contents\":\"contents\",\"engine_version\":\"0.1.0\",\"engine\":\"dynamo\",\"engine_metadata\":\"metadata\",\"site_url\":\"\",\"repository_url\":\"\",\"contains_binaries\":false,\"node_libraries\":[],\"copyright_holder\":\"Dynamo Team\",\"copyright_year\":\"2021\",\"compatibility_matrix\":\"\",\"release_notes_url\":\"\"}"));
+            Assert.That(request.RequestBody.AsJson().Equals("{\"file_hash\":null,\"name\":\"Third .NET Package\",\"version\":\"2.1.0\",\"description\":\"\",\"group\":\"group\",\"keywords\":[\"neat\",\"ok\"],\"dependencies\":[{\"name\":\"peter\",\"version\":\"0.1.0\"},{\"name\":\"stephen\",\"version\":\"0.1.0\"}],\"host_dependencies\":[],\"contents\":\"contents\",\"engine_version\":\"0.1.0\",\"engine\":\"dynamo\",\"engine_metadata\":\"metadata\",\"site_url\":\"\",\"repository_url\":\"\",\"contains_binaries\":false,\"node_libraries\":[],\"copyright_holder\":\"Dynamo Team\",\"copyright_year\":\"2021\",\"compatibility_matrix\":null,\"release_notes_url\":\"\"}"));
             Console.WriteLine(request.RequestBody.AsJson());
         }
         
@@ -70,11 +70,11 @@ public void UploadDynamoPackageWithHostDependencyTest()
             var keywords = new List<string>() { "Civil" };
             var nv = new PackageVersionUploadRequestBody("Third .NET Package", "2.1.0", "", keywords, "contents", "dynamo", "0.1.0", "metadata", "group",
                             new List<PackageDependency>() { new PackageDependency("Ram", "0.1.0"), new PackageDependency("Ian", "0.1.0") }, "", "",
-                            false, new List<String>(), new List<String>() { "Civil3D" }, "Dynamo Team", "2021", "", "");
+                            false, new List<String>(), new List<String>() { "Civil3D" }, "Dynamo Team", "2021", null, "");
 
             var files = new List<string>() { "../test/pedro.dyf", "../test/RootNode.dyf" };
             var request = new PackageVersionUpload(nv, files);
-            Assert.That(request.RequestBody.AsJson().Equals("{\"file_hash\":null,\"name\":\"Third .NET Package\",\"version\":\"2.1.0\",\"description\":\"\",\"group\":\"group\",\"keywords\":[\"Civil\"],\"dependencies\":[{\"name\":\"Ram\",\"version\":\"0.1.0\"},{\"name\":\"Ian\",\"version\":\"0.1.0\"}],\"host_dependencies\":[\"Civil3D\"],\"contents\":\"contents\",\"engine_version\":\"0.1.0\",\"engine\":\"dynamo\",\"engine_metadata\":\"metadata\",\"site_url\":\"\",\"repository_url\":\"\",\"contains_binaries\":false,\"node_libraries\":[],\"copyright_holder\":\"Dynamo Team\",\"copyright_year\":\"2021\",\"compatibility_matrix\":\"\",\"release_notes_url\":\"\"}"));
+            Assert.That(request.RequestBody.AsJson().Equals("{\"file_hash\":null,\"name\":\"Third .NET Package\",\"version\":\"2.1.0\",\"description\":\"\",\"group\":\"group\",\"keywords\":[\"Civil\"],\"dependencies\":[{\"name\":\"Ram\",\"version\":\"0.1.0\"},{\"name\":\"Ian\",\"version\":\"0.1.0\"}],\"host_dependencies\":[\"Civil3D\"],\"contents\":\"contents\",\"engine_version\":\"0.1.0\",\"engine\":\"dynamo\",\"engine_metadata\":\"metadata\",\"site_url\":\"\",\"repository_url\":\"\",\"contains_binaries\":false,\"node_libraries\":[],\"copyright_holder\":\"Dynamo Team\",\"copyright_year\":\"2021\",\"compatibility_matrix\":null,\"release_notes_url\":\"\"}"));
             Console.WriteLine(request.RequestBody.AsJson());
         }
         
@@ -83,7 +83,7 @@ public void UploadDynamoPackageVersionWithFilesTest()
         {
             var keywords = new List<string>() { "neat", "ok" };
             var nv = new PackageVersionUploadRequestBody("Third .NET Package", "2.1.0", "", keywords, "contents", "dynamo", "0.1.0", "metadata", "group",
-                new List<PackageDependency>() { new PackageDependency("peter", "0.1.0"), new PackageDependency("stephen", "0.1.0") }, "", "", false, new List<String>(), new List<String>(), "", "", "", "");
+                new List<PackageDependency>() { new PackageDependency("peter", "0.1.0"), new PackageDependency("stephen", "0.1.0") }, "", "", false, new List<String>(), new List<String>(), "", "", null, "");
 
             var files = new List<string>() {Assembly.GetExecutingAssembly().Location };
 
@@ -160,6 +160,37 @@ public void ListHostsTest()
             Console.WriteLine(JsonSerializer.Serialize(hostsResponse.content));
             Assert.That(hostsResponse.content.Count, Is.EqualTo(5));
         }
-        
+
+        [Test]
+
+        public void TestCompatibilityDeserializationTest()
+        {
+            var mockResponse= @"[
+                {
+                    ""name"" : ""dynamo"",
+                    ""versions"" : [""2.17"",""2.18""],
+                    ""min"" : ""2.17"",
+                    ""max"" : ""3.0""
+                },
+                {
+                    ""name"" : ""revit"",
+                    ""versions"" : [""2024"",""2025""],
+                    ""min"" : ""2025""
+                },
+                {
+                    ""name"" : ""civil3d"",
+                    ""min"" : ""2025"",
+                    ""max"" : ""2024""
+                },
+                {
+                    ""name"" : "".net"",
+                    ""max"" : ""net8""
+                }
+            ]";
+            var cm = JsonSerializer.Deserialize<List<PackageCompatibility>>(mockResponse);
+            Assert.That(cm, !Is.Null);
+            Assert.That(cm, Has.Count.EqualTo(4));
+        }
+
     }
 }
\ No newline at end of file