diff --git a/CHANGELOG.md b/CHANGELOG.md
index ade0c1784..b8d330783 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # CHANGELOG
 
+## v5.6.0 (2023-08-31)
+
+- Add ability to compare an EasyPost object to a parameter set object via `Matches` function
+  - Users can define a custom `Matches` function on any parameter set class
+- Fix parameter set serialization that was causing issues when altering and reusing parameter sets
+
 ## v5.5.0 (2023-08-29)
 
 - Add custom parameter sets (`CreateFedEx`, `CreateUps`) for carrier account creation API calls
diff --git a/EasyPost.Tests/ParametersTests/ParametersTest.cs b/EasyPost.Tests/ParametersTests/ParametersTest.cs
index 0f47c9282..8ee9ea065 100644
--- a/EasyPost.Tests/ParametersTests/ParametersTest.cs
+++ b/EasyPost.Tests/ParametersTests/ParametersTest.cs
@@ -108,6 +108,43 @@ public void TestParametersToDictionaryWithSubDictionary()
             Assert.Equal(streetB, addressData["street1"]);
         }
 
+        /// <summary>
+        ///     This test proves that you can reuse a parameter object, and that re-serializing it will take into account any changes made to its properties since the last serialization.
+        /// </summary>
+        [Fact]
+        [Testing.Logic]
+        public void TestReusingParameterSets()
+        {
+            var parameters = new Parameters.Shipment.All
+            {
+                BeforeId = null,
+            };
+
+            // null values should not be serialized
+            var parametersDictionary = parameters.ToDictionary();
+            Assert.False(parametersDictionary.ContainsKey("before_id"));
+
+            parameters.BeforeId = "1";
+
+            // now that the property has a value, it should be serialized
+            parametersDictionary = parameters.ToDictionary();
+            Assert.True(parametersDictionary.ContainsKey("before_id"));
+            Assert.Equal("1", parametersDictionary["before_id"]);
+
+            parameters.BeforeId = "2";
+
+            // the new value should be serialized
+            parametersDictionary = parameters.ToDictionary();
+            Assert.True(parametersDictionary.ContainsKey("before_id"));
+            Assert.Equal("2", parametersDictionary["before_id"]);
+
+            parameters.BeforeId = null;
+
+            // null values should not be serialized
+            parametersDictionary = parameters.ToDictionary();
+            Assert.False(parametersDictionary.ContainsKey("before_id"));
+        }
+
         [Fact]
         [Testing.Exception]
         public void TestRequiredAndOptionalParameterValidation()
diff --git a/EasyPost.nuspec b/EasyPost.nuspec
index 178793370..fe599e975 100644
--- a/EasyPost.nuspec
+++ b/EasyPost.nuspec
@@ -3,7 +3,7 @@
     <metadata>
         <id>EasyPost-Official</id>
         <title>EasyPost (Official)</title>
-        <version>5.5.0</version>
+        <version>5.6.0</version>
         <authors>EasyPost</authors>
         <owners>EasyPost</owners>
         <projectUrl>https://www.easypost.com</projectUrl>
diff --git a/EasyPost/Parameters/BaseParameters.cs b/EasyPost/Parameters/BaseParameters.cs
index 36892740b..a3e09b5d2 100644
--- a/EasyPost/Parameters/BaseParameters.cs
+++ b/EasyPost/Parameters/BaseParameters.cs
@@ -58,6 +58,8 @@ public virtual Dictionary<string, object> ToDictionary()
             // Bad stuff could happen if we allow end-users to convert a parameter object to a dictionary themselves and try to use it in the normal functions
             // In particular, a lot of the normal functions do additional wrapping of their dictionaries, which would result in invalid JSON schemas being sent to the API
 
+            _parameterDictionary = new Dictionary<string, object?>();
+
             // Construct the dictionary of all parameters
             PropertyInfo[] properties = GetType().GetProperties(BindingFlags.Instance |
                                                                 BindingFlags.NonPublic |
@@ -106,6 +108,8 @@ public virtual Dictionary<string, object> ToDictionary()
         /// <returns><see cref="Dictionary{TKey,TValue}" /> of parameters.</returns>
         public virtual Dictionary<string, object> ToSubDictionary(Type parentParameterObjectType)
         {
+            _parameterDictionary = new Dictionary<string, object?>();
+
             // Construct the dictionary of all parameters
             PropertyInfo[] properties = GetType().GetProperties(BindingFlags.Instance |
                                                                 BindingFlags.NonPublic |
diff --git a/EasyPost/Properties/VersionInfo.cs b/EasyPost/Properties/VersionInfo.cs
index cb00bc913..85fe7ac34 100644
--- a/EasyPost/Properties/VersionInfo.cs
+++ b/EasyPost/Properties/VersionInfo.cs
@@ -2,6 +2,6 @@
 
 // Version information for an assembly must follow semantic versioning
 // When releasing a release candidate, append a 4th digit being the number of the release candidate
-[assembly: AssemblyVersion("5.5.0")]
-[assembly: AssemblyFileVersion("5.5.0")]
-[assembly: AssemblyInformationalVersion("5.5.0")]
+[assembly: AssemblyVersion("5.6.0")]
+[assembly: AssemblyFileVersion("5.6.0")]
+[assembly: AssemblyInformationalVersion("5.6.0")]