Use a Source Generator to extract the Version information

Kiota.Generated/KiotaGenerated.csproj

@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+    <LangVersion>latest</LangVersion>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.4.0" ExcludeAssets="runtime" />
+    <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.3" ExcludeAssets="runtime" />
+  </ItemGroup>
+
+  <Target Name="DoSthAfterPublish1" AfterTargets="Publish">
+    <Copy SourceFiles="..\Kiota.Builder\Kiota.Builder.csproj" />
+  </Target>
+
+</Project>

Kiota.Generated/KiotaVersionGenerator.cs

@@ -0,0 +1,49 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Xml;
+using Microsoft.CodeAnalysis;
+
+[Generator]
+public class KiotaVersionGenerator : ISourceGenerator
+{
+    public void Execute(GeneratorExecutionContext context)
+    {
+        var mainSyntaxTree = context.Compilation.SyntaxTrees
+                            .First(static x => x.HasCompilationUnitRoot);
+
+        var directory = Path.GetDirectoryName(mainSyntaxTree.FilePath);
+
+        var version = "unknown";
+        try {
+            XmlDocument csproj = new XmlDocument();
+            csproj.Load(Path.Combine(directory, "..", "Microsoft.Kiota.Http.HttpClientLibrary.csproj"));
+
+            version = csproj.GetElementsByTagName("VersionPrefix")[0].InnerText;
+        } catch (Exception e)
+        {
+            throw new SystemException("KiotaVersionGenerator expanded in an invalid project, missing 'Microsoft.Kiota.Http.HttpClientLibrary.csproj' file.", e);
+        }
+
+        string source = $@"// <auto-generated/>
+namespace Microsoft.Kiota.Http.Generated
+{{
+    public static class Version
+    {{
+        public static string Current()
+        {{
+            return ""{version}"";
+        }}
+    }}
+}}
+";
+
+        // Add the source code to the compilation
+        context.AddSource($"KiotaVersion.g.cs", source);
+    }
+
+    public void Initialize(GeneratorInitializationContext context)
+    {
+        // No initialization required for this one
+    }
+}

Microsoft.Kiota.Http.HttpClientLibrary.sln

@@ -12,6 +12,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Microsoft.Kiota.Http.HttpClientLibrary.Tests", "Microsoft.Kiota.Http.HttpClientLibrary.Tests\Microsoft.Kiota.Http.HttpClientLibrary.Tests.csproj", "{CCD20728-D593-48F8-8627-6E7A57B31A43}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "KiotaGenerated", "Kiota.Generated\KiotaGenerated.csproj", "{6667C82F-EFF1-4D7C-828D-F981629C8256}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -46,6 +48,18 @@ Global
 		{CCD20728-D593-48F8-8627-6E7A57B31A43}.Release|x64.Build.0 = Release|Any CPU
 		{CCD20728-D593-48F8-8627-6E7A57B31A43}.Release|x86.ActiveCfg = Release|Any CPU
 		{CCD20728-D593-48F8-8627-6E7A57B31A43}.Release|x86.Build.0 = Release|Any CPU
+		{6667C82F-EFF1-4D7C-828D-F981629C8256}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{6667C82F-EFF1-4D7C-828D-F981629C8256}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{6667C82F-EFF1-4D7C-828D-F981629C8256}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{6667C82F-EFF1-4D7C-828D-F981629C8256}.Debug|x64.Build.0 = Debug|Any CPU
+		{6667C82F-EFF1-4D7C-828D-F981629C8256}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{6667C82F-EFF1-4D7C-828D-F981629C8256}.Debug|x86.Build.0 = Debug|Any CPU
+		{6667C82F-EFF1-4D7C-828D-F981629C8256}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{6667C82F-EFF1-4D7C-828D-F981629C8256}.Release|Any CPU.Build.0 = Release|Any CPU
+		{6667C82F-EFF1-4D7C-828D-F981629C8256}.Release|x64.ActiveCfg = Release|Any CPU
+		{6667C82F-EFF1-4D7C-828D-F981629C8256}.Release|x64.Build.0 = Release|Any CPU
+		{6667C82F-EFF1-4D7C-828D-F981629C8256}.Release|x86.ActiveCfg = Release|Any CPU
+		{6667C82F-EFF1-4D7C-828D-F981629C8256}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

src/Microsoft.Kiota.Http.HttpClientLibrary.csproj

@@ -35,6 +35,7 @@
     <PackageReference Include="Microsoft.Kiota.Abstractions" Version="1.0.0-rc.3" />
     <PackageReference Include="System.Diagnostics.DiagnosticSource" Version="7.0.0" />
     <PackageReference Include="System.Text.Json" Version="7.0.1" />
+    <ProjectReference Include="..\Kiota.Generated\KiotaGenerated.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
   <PropertyGroup Condition="'$(TF_BUILD)' == 'true'">

src/Middleware/Options/UserAgentHandlerOption.cs

@@ -25,6 +25,6 @@ public class UserAgentHandlerOption : IRequestOption
         /// <summary>
         /// The product version to append to the user agent header
         /// </summary>
-        public string ProductVersion { get; set; } = FileVersionInfo.GetVersionInfo(Assembly.GetExecutingAssembly().Location).ProductVersion.Split('+').First();
+        public string ProductVersion { get; set; } = Microsoft.Kiota.Http.Generated.Version.Current();
     }
 }