diff --git a/.github/workflows/dotnet-core.yml b/.github/workflows/dotnet-core.yml
index af47304..a91cefb 100644
--- a/.github/workflows/dotnet-core.yml
+++ b/.github/workflows/dotnet-core.yml
@@ -12,14 +12,18 @@ jobs:
     runs-on: windows-latest
     steps:
     - uses: actions/checkout@v2
-    - name: Setup .NET 2.1.X Core
-      uses: actions/setup-dotnet@v1
+    - name: Setup .NET 6.X
+      uses: actions/setup-dotnet@v2
       with:
-        dotnet-version: 2.1.x
-    - name: Setup .NET 3.1.X Core
-      uses: actions/setup-dotnet@v1
+        dotnet-version: 6.x
+    - name: Setup .NET 7.X
+      uses: actions/setup-dotnet@v2
       with:
-        dotnet-version: 3.1.x
+        dotnet-version: 7.x
+    - name: Setup .NET 8.X
+      uses: actions/setup-dotnet@v2
+      with:
+        dotnet-version: 8.x
     - name: where are we?
       run: ls
     - name: Install dependencies
diff --git a/Source/Expressive.Tests/Expressive.Tests.csproj b/Source/Expressive.Tests/Expressive.Tests.csproj
index 2d6c68e..5789ea3 100644
--- a/Source/Expressive.Tests/Expressive.Tests.csproj
+++ b/Source/Expressive.Tests/Expressive.Tests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.1;netcoreapp3.1;net45</TargetFrameworks>
+    <TargetFrameworks>net6.0;net7.0;net8.0</TargetFrameworks>
 
     <IsPackable>false</IsPackable>
 
diff --git a/Source/Expressive/Exceptions/ExpressiveException.cs b/Source/Expressive/Exceptions/ExpressiveException.cs
index e87cd13..fe1dbab 100644
--- a/Source/Expressive/Exceptions/ExpressiveException.cs
+++ b/Source/Expressive/Exceptions/ExpressiveException.cs
@@ -5,9 +5,6 @@ namespace Expressive.Exceptions
     /// <summary>
     /// The main exposed <see cref="Exception"/> for users of an Expression. Check the InnerException for more information.
     /// </summary>
-#if !NETSTANDARD1_4
-    [Serializable]
-#endif
     public sealed class ExpressiveException : Exception
     {
         internal ExpressiveException(string message) : base(message)
diff --git a/Source/Expressive/Exceptions/FunctionNameAlreadyRegisteredException.cs b/Source/Expressive/Exceptions/FunctionNameAlreadyRegisteredException.cs
index 51e31a3..0ff6ea9 100644
--- a/Source/Expressive/Exceptions/FunctionNameAlreadyRegisteredException.cs
+++ b/Source/Expressive/Exceptions/FunctionNameAlreadyRegisteredException.cs
@@ -1,18 +1,11 @@
 using System;
 using Expressive.Functions;
-#if !NETSTANDARD1_4
-using System.Runtime.Serialization;
-using System.Security.Permissions;
-#endif
 
 namespace Expressive.Exceptions
 {
     /// <summary>
     /// Represents an error that is thrown when registering an <see cref="IFunction"/> and the name is already used.
     /// </summary>
-#if !NETSTANDARD1_4
-    [Serializable]
-#endif
     public sealed class FunctionNameAlreadyRegisteredException : Exception
     {
         /// <summary>
@@ -29,20 +22,5 @@ internal FunctionNameAlreadyRegisteredException(string name)
         {
             this.Name = name;
         }
-
-#if !NETSTANDARD1_4
-        /// <summary>
-        /// Set the <see cref="SerializationInfo"/> with information about this exception.
-        /// </summary>
-        /// <param name="info">The <see cref="SerializationInfo"/> that holds the serialized object data about the exception being thrown.</param>
-        /// <param name="context">The <see cref="StreamingContext"/> that contains contextual information about the source or destination.</param>
-        [SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]
-        public override void GetObjectData(SerializationInfo info, StreamingContext context)
-        {
-            base.GetObjectData(info, context);
-
-            info.AddValue("Name", Name);
-        }
-#endif
     }
 }
diff --git a/Source/Expressive/Exceptions/MissingParticipantException.cs b/Source/Expressive/Exceptions/MissingParticipantException.cs
index d6eecd0..84c68c1 100644
--- a/Source/Expressive/Exceptions/MissingParticipantException.cs
+++ b/Source/Expressive/Exceptions/MissingParticipantException.cs
@@ -5,9 +5,6 @@ namespace Expressive.Exceptions
     /// <summary>
     /// Represents an error that is thrown when one side of an operation is missing inside an <see cref="Expression"/>.
     /// </summary>
-#if !NETSTANDARD1_4
-    [Serializable]
-#endif
     public sealed class MissingParticipantException : Exception
     {
         /// <summary>
diff --git a/Source/Expressive/Exceptions/MissingTokenException.cs b/Source/Expressive/Exceptions/MissingTokenException.cs
index 4959792..5d3b418 100644
--- a/Source/Expressive/Exceptions/MissingTokenException.cs
+++ b/Source/Expressive/Exceptions/MissingTokenException.cs
@@ -1,17 +1,10 @@
 using System;
-#if !NETSTANDARD1_4
-using System.Runtime.Serialization;
-using System.Security.Permissions;
-#endif
 
 namespace Expressive.Exceptions
 {
     /// <summary>
     /// Represents an error that is thrown when a missing token is detected inside an <see cref="Expression"/>.
     /// </summary>
-#if !NETSTANDARD1_4
-    [Serializable]
-#endif
     public sealed class MissingTokenException : Exception
     {
         /// <summary>
@@ -29,20 +22,5 @@ internal MissingTokenException(string message, char missingToken)
         {
             this.MissingToken = missingToken;
         }
-
-#if !NETSTANDARD1_4
-        /// <summary>
-        /// Set the <see cref="SerializationInfo"/> with information about this exception.
-        /// </summary>
-        /// <param name="info">The <see cref="SerializationInfo"/> that holds the serialized object data about the exception being thrown.</param>
-        /// <param name="context">The <see cref="StreamingContext"/> that contains contextual information about the source or destination.</param>
-        [SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]
-        public override void GetObjectData(SerializationInfo info, StreamingContext context)
-        {
-            base.GetObjectData(info, context);
-
-            info.AddValue("MissingToken", MissingToken);
-        }
-#endif
     }
 }
diff --git a/Source/Expressive/Exceptions/OperatorNameAlreadyRegisteredException.cs b/Source/Expressive/Exceptions/OperatorNameAlreadyRegisteredException.cs
index 059322d..5e30fef 100644
--- a/Source/Expressive/Exceptions/OperatorNameAlreadyRegisteredException.cs
+++ b/Source/Expressive/Exceptions/OperatorNameAlreadyRegisteredException.cs
@@ -1,19 +1,11 @@
 using System;
 using Expressive.Operators;
 
-#if !NETSTANDARD1_4
-using System.Runtime.Serialization;
-using System.Security.Permissions;
-#endif
-
 namespace Expressive.Exceptions
 {
     /// <summary>
     /// Represents an error that is thrown when registering an <see cref="IOperator"/> and the name is already used.
     /// </summary>
-#if !NETSTANDARD1_4
-    [Serializable]
-#endif
     public sealed class OperatorNameAlreadyRegisteredException : Exception
     {
         /// <summary>
@@ -30,20 +22,5 @@ internal OperatorNameAlreadyRegisteredException(string tag)
         {
             this.Tag = tag;
         }
-
-#if !NETSTANDARD1_4
-        /// <summary>
-        /// Set the <see cref="SerializationInfo"/> with information about this exception.
-        /// </summary>
-        /// <param name="info">The <see cref="SerializationInfo"/> that holds the serialized object data about the exception being thrown.</param>
-        /// <param name="context">The <see cref="StreamingContext"/> that contains contextual information about the source or destination.</param>
-        [SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]
-        public override void GetObjectData(SerializationInfo info, StreamingContext context)
-        {
-            base.GetObjectData(info, context);
-
-            info.AddValue("Tag", Tag);
-        }
-#endif
     }
 }
diff --git a/Source/Expressive/Exceptions/ParameterCountMismatchException.cs b/Source/Expressive/Exceptions/ParameterCountMismatchException.cs
index 0541d15..b46ac1f 100644
--- a/Source/Expressive/Exceptions/ParameterCountMismatchException.cs
+++ b/Source/Expressive/Exceptions/ParameterCountMismatchException.cs
@@ -5,9 +5,6 @@ namespace Expressive.Exceptions
     /// <summary>
     /// Represents an error that is thrown when a function has an incorrect number of parameters.
     /// </summary>
-#if !NETSTANDARD1_4
-    [Serializable]
-#endif
     public sealed class ParameterCountMismatchException : Exception
     {
         /// <summary>
diff --git a/Source/Expressive/Exceptions/UnrecognisedTokenException.cs b/Source/Expressive/Exceptions/UnrecognisedTokenException.cs
index 1d94881..37184b8 100644
--- a/Source/Expressive/Exceptions/UnrecognisedTokenException.cs
+++ b/Source/Expressive/Exceptions/UnrecognisedTokenException.cs
@@ -1,18 +1,10 @@
 using System;
 
-#if !NETSTANDARD1_4
-using System.Runtime.Serialization;
-using System.Security.Permissions;
-#endif
-
 namespace Expressive.Exceptions
 {
     /// <summary>
     /// Represents an error that is thrown when a token is not recognised inside an <see cref="Expression"/>.
     /// </summary>
-#if !NETSTANDARD1_4
-    [Serializable]
-#endif
     public sealed class UnrecognisedTokenException : Exception
     {
         /// <summary>
@@ -29,20 +21,5 @@ internal UnrecognisedTokenException(string token)
         {
             this.Token = token;
         }
-
-#if !NETSTANDARD1_4
-        /// <summary>
-        /// Set the <see cref="SerializationInfo"/> with information about this exception.
-        /// </summary>
-        /// <param name="info">The <see cref="SerializationInfo"/> that holds the serialized object data about the exception being thrown.</param>
-        /// <param name="context">The <see cref="StreamingContext"/> that contains contextual information about the source or destination.</param>
-        [SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]
-        public override void GetObjectData(SerializationInfo info, StreamingContext context)
-        {
-            base.GetObjectData(info, context);
-
-            info.AddValue("Token", Token);
-        }
-#endif
     }
 }
diff --git a/Source/Expressive/Expression.cs b/Source/Expressive/Expression.cs
index 6a25b99..76ff83d 100644
--- a/Source/Expressive/Expression.cs
+++ b/Source/Expressive/Expression.cs
@@ -199,11 +199,7 @@ public void EvaluateAsync<T>(Action<string, T> callback, IDictionary<string, obj
                 throw new ArgumentNullException(nameof(callback));
             }
 
-#if NETSTANDARD1_4
             Task.Run(() =>
-#else
-            ThreadPool.QueueUserWorkItem((o) =>
-#endif
             {
                 var result = default(T);
                 string message = null;
diff --git a/Source/Expressive/Expressive.csproj b/Source/Expressive/Expressive.csproj
index 3765f2f..546c3a4 100644
--- a/Source/Expressive/Expressive.csproj
+++ b/Source/Expressive/Expressive.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard1.4;netstandard2.0;net45</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0</TargetFrameworks>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>..\ExpressiveStrongName.snk</AssemblyOriginatorKeyFile>
     <AssemblyVersion>0.0.0.0</AssemblyVersion>
@@ -13,7 +13,7 @@
     <PackageProjectUrl>https://github.com/bijington/expressive</PackageProjectUrl>
     <Product>Expressive Parser</Product>
     <Description>A multi-platform expression parsing and evaluating framework.</Description>
-    <Copyright>Copyright(c) 2020 Shaun Lawrence</Copyright>
+    <Copyright>Copyright(c) 2024 Shaun Lawrence</Copyright>
     <PackageTags>Expression Parser Evaluator Cross-Platform NET Standard Xamarin Xamarin.Forms</PackageTags>
     <PackageIcon>logo-64.png</PackageIcon>
     <PackageIconUrl />
@@ -50,4 +50,4 @@
     </PackageReference>
   </ItemGroup>
 
-</Project>
+</Project>
\ No newline at end of file
diff --git a/Source/Expressive/Helpers/TypeHelper.cs b/Source/Expressive/Helpers/TypeHelper.cs
index da3e5c2..441e673 100644
--- a/Source/Expressive/Helpers/TypeHelper.cs
+++ b/Source/Expressive/Helpers/TypeHelper.cs
@@ -14,68 +14,7 @@ public static class TypeHelper
         /// <returns>The code of the underlying type, or <see cref="TypeCode.Empty"/> if type is null.</returns>
         public static TypeCode GetTypeCode(object value)
         {
-            var typeCode = TypeCode.Object;
-
-#if NETSTANDARD1_4
-            // TODO: Explore converting all numbers to decimal and simplifying all of this.
-
-            switch (value)
-            {
-                case bool _:
-                    typeCode = TypeCode.Boolean;
-                    break;
-                case byte _:
-                    typeCode = TypeCode.Byte;
-                    break;
-                case char _:
-                    typeCode = TypeCode.Char;
-                    break;
-                case DateTime _:
-                    typeCode = TypeCode.DateTime;
-                    break;
-                case decimal _:
-                    typeCode = TypeCode.Decimal;
-                    break;
-                case double _:
-                    typeCode = TypeCode.Double;
-                    break;
-                case long _:
-                    typeCode = TypeCode.Int64;
-                    break;
-                case int _:
-                    typeCode = TypeCode.Int32;
-                    break;
-                case short _:
-                    typeCode = TypeCode.Int16;
-                    break;
-                case sbyte _:
-                    typeCode = TypeCode.SByte;
-                    break;
-                case float _:
-                    typeCode = TypeCode.Single;
-                    break;
-                case string _:
-                    typeCode = TypeCode.String;
-                    break;
-                case ushort _:
-                    typeCode = TypeCode.UInt16;
-                    break;
-                case uint _:
-                    typeCode = TypeCode.UInt32;
-                    break;
-                case ulong _:
-                    typeCode = TypeCode.UInt64;
-                    break;
-                case null:
-                    typeCode = TypeCode.Empty;
-                    break;
-            }
-
-#else
-            typeCode = Type.GetTypeCode(value?.GetType());
-#endif
-
-            return typeCode;
+            return Type.GetTypeCode(value?.GetType());
         }
     }
 }