diff --git a/gitversion.yml b/gitversion.yml
index 19d2b4ec..f4c27692 100644
--- a/gitversion.yml
+++ b/gitversion.yml
@@ -20,7 +20,7 @@ branches:
   release: # Release and preview versions.
     # branch:  release/6.0.0-preview-3 -- must be same as git tag without leading 'v'.
     # version: {6-0-0-preview-3}       -- taken from git tag only
-    regex: ^(release[/-]|master)
+    regex: ^(release[/-]|master|pdfsharp-extended)
     # Must not have mode set to be mainline?
     increment: None
     tag: ''
diff --git a/src/Directory.Build.props b/src/Directory.Build.props
index ec393bfd..2f5764e4 100644
--- a/src/Directory.Build.props
+++ b/src/Directory.Build.props
@@ -28,8 +28,8 @@
     <Product>PDFsharp</Product>
     <Company>empira Software</Company>
     <Copyright>© 2025 empira</Copyright>
-    <Authors>PDFsharp Team</Authors>
-    <Owners>empira Software GmbH</Owners>
+    <Authors>PDFsharp Team, KDS-NTG</Authors>
+    <Owners>KDS-NTG</Owners>
   </PropertyGroup>
 
   <PropertyGroup>
diff --git a/src/foundation/nuget/src/Directory.Build.props b/src/foundation/nuget/src/Directory.Build.props
index 618588a9..4a6e7b24 100644
--- a/src/foundation/nuget/src/Directory.Build.props
+++ b/src/foundation/nuget/src/Directory.Build.props
@@ -1,4 +1,4 @@
-<Project>
+<Project>
   <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
 
   <ItemGroup>
@@ -12,11 +12,11 @@
     <NuGetReleaseNotes>@(ReleaseNotesFileContents->'%(Identity)', '%0d')</NuGetReleaseNotes>
     <DebugBuildMessage>***** THIS IS A DEBUG BUILD - DO NOT PUBLISH *****%0d</DebugBuildMessage>
 
-    <!--<NuGetProjectUrl>https://docs.pdfsharp.net</NuGetProjectUrl>-->
-    <NuGetProjectUrl>https://docs.pdfsharp.net</NuGetProjectUrl>
-    <NuGetTags_PdfSharp>PDFsharp PDF creation</NuGetTags_PdfSharp>
-    <NuGetTags_MigraDoc>MigraDoc PDFsharp PDF Document Generation</NuGetTags_MigraDoc>
-  </PropertyGroup>
+		<!--<NuGetProjectUrl>https://docs.pdfsharp.net</NuGetProjectUrl>-->
+		<NuGetProjectUrl>https://github.com/KDS/PDFsharp/tree/pdfsharp-6-2-1-extended</NuGetProjectUrl>
+		<NuGetTags_PdfSharp>PDFsharp PDF creation signature</NuGetTags_PdfSharp>
+		<NuGetTags_MigraDoc>MigraDoc PDFsharp PDF Document Generation</NuGetTags_MigraDoc>
+	</PropertyGroup>
 
   <Target Name="SetNuspecProperties" BeforeTargets="GenerateNuspec">
 
diff --git a/src/foundation/nuget/src/PDFsharp.NuGet/Description.txt b/src/foundation/nuget/src/PDFsharp.NuGet/Description.txt
index b6b011a5..eab1affb 100644
--- a/src/foundation/nuget/src/PDFsharp.NuGet/Description.txt
+++ b/src/foundation/nuget/src/PDFsharp.NuGet/Description.txt
@@ -3,3 +3,11 @@ PDFsharp is the Open Source library for creating and modifying PDF documents usi
 This package does not depend on Windows and can be used on any .NET compatible platform including Linux and macOS.
 
 See https://docs.pdfsharp.net for details.
+
+EXTENDED: this is an extended version with additional features:
+* Do not override XMP metadata if using option ManualXmpGeneration
+* File attachment annotations
+* Embedded file checksum property
+And bug fixes:
+* https://github.com/empira/PDFsharp/issues/248 (signature failing when document is malformed)
+* https://github.com/empira/PDFsharp/issues/71 (Exception when pointing multiple PdfFileSpecification to a single PdfEmbeddedFileStream)
\ No newline at end of file
diff --git a/src/foundation/nuget/src/PDFsharp.NuGet/PDFsharp.NuGet.csproj b/src/foundation/nuget/src/PDFsharp.NuGet/PDFsharp.NuGet.csproj
index 1139a742..8ba63529 100644
--- a/src/foundation/nuget/src/PDFsharp.NuGet/PDFsharp.NuGet.csproj
+++ b/src/foundation/nuget/src/PDFsharp.NuGet/PDFsharp.NuGet.csproj
@@ -13,10 +13,10 @@
     <IsPackable>true</IsPackable>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <NuspecFile>$(MSBuildThisFileDirectory)$(MSBuildProjectName).nuspec</NuspecFile>
-    <NuGetId>PDFsharp</NuGetId>
-    <NuGetTitle>PDFsharp for Windows and Linux</NuGetTitle>
+    <NuGetId>PDFsharp-extended</NuGetId>
+    <NuGetTitle>PDFsharp for Windows and Linux, with extra features: file attachment annotations, embedded file checksum, preservation of XMP data, and bug fixes.</NuGetTitle>
     <NuGetDescription Condition=" '$(Configuration)'=='Debug' ">$(DebugBuildMessage)%0D$(NuGetDescription)</NuGetDescription>
-    <NuGetSummary>A .NET library for processing PDF.</NuGetSummary>
+    <NuGetSummary>A .NET library for processing PDF. With extra features: file attachment annotations, embedded file checksum, preservation of XMP data, and bug fixes.</NuGetSummary>
     <NuGetTags>$(NuGetTags_PdfSharp)</NuGetTags>
   </PropertyGroup>
 
diff --git a/src/foundation/nuget/src/PDFsharp.NuGet/PDFsharp.NuGet.nuspec b/src/foundation/nuget/src/PDFsharp.NuGet/PDFsharp.NuGet.nuspec
index 4c01c173..cdade499 100644
--- a/src/foundation/nuget/src/PDFsharp.NuGet/PDFsharp.NuGet.nuspec
+++ b/src/foundation/nuget/src/PDFsharp.NuGet/PDFsharp.NuGet.nuspec
@@ -15,7 +15,7 @@
         <releaseNotes>$releaseNotes$</releaseNotes>
         <copyright>$copyright$</copyright>
         <tags>$tags$</tags>
-        <repository type="git" url="https://github.com/empira/PDFsharp" branch="master" commit="" />
+        <repository type="git" url="https://github.com/KDS/PDFsharp" branch="pdfsharp-6-2-1-extended" commit="" />
         <title>$title$</title>
         <dependencies>
             <group targetFramework="net6.0">
diff --git a/src/foundation/nuget/src/PDFsharp.NuGet/README.md b/src/foundation/nuget/src/PDFsharp.NuGet/README.md
index 4e60f763..ec206725 100644
--- a/src/foundation/nuget/src/PDFsharp.NuGet/README.md
+++ b/src/foundation/nuget/src/PDFsharp.NuGet/README.md
@@ -5,3 +5,11 @@ PDFsharp is the Open Source library for creating and modifying PDF documents usi
 This package does not depend on Windows and can be used on any .NET compatible platform including Linux and macOS.
 
 See [docs.pdfsharp.net](https://docs.pdfsharp.net) for details.
+
+EXTENDED: this is an extended version with additional features:
+* Do not override XMP metadata if using option ManualXmpGeneration
+* File attachment annotations
+* Embedded file checksum property
+And bug fixes:
+* https://github.com/empira/PDFsharp/issues/248 (signature failing when document is malformed)
+* https://github.com/empira/PDFsharp/issues/71 (Exception when pointing multiple PdfFileSpecification to a single PdfEmbeddedFileStream)
\ No newline at end of file
diff --git a/src/foundation/nuget/src/PDFsharp.NuGet/ReleaseNotes.txt b/src/foundation/nuget/src/PDFsharp.NuGet/ReleaseNotes.txt
index f5df80ae..c8a45500 100644
--- a/src/foundation/nuget/src/PDFsharp.NuGet/ReleaseNotes.txt
+++ b/src/foundation/nuget/src/PDFsharp.NuGet/ReleaseNotes.txt
@@ -1,6 +1,22 @@
-This is a version of PDFsharp compatible with .NET 6 and higher.
+This is a version of PDFsharp compatible with .NET 6 and higher.
 The package ‘PdfSharp’ can be used on any platform including Windows and Linux. The Target Frameworks are ‘net6.0’, ‘net8.0’ and ‘netstandard2.0’.
 The packages ‘PDFsharp-gdi’ and ‘PDFsharp-wpf’ can be used under Windows only. The Target Frameworks are ‘net6.0-windows’, ‘net8.0-windows’ and ‘net462’.
 We also publish packages that contain PDFsharp plus MigraDoc.
 See the project docs site for further information:
 https://docs.pdfsharp.net/link/readme-v6.2.html
+
+
+
+PDFsharp-extended:
+
+v1.2.0
+* Synchronized with PdfSharp 6.2.1 (including natively multi-targeting netstandard/fx/net6 and digital signatures)
+v1.1.1
+* Fix issue #80 (allow detection of JPEG APP2 ICC_PROFILE headers)
+v1.1.0
+* Merged PR#2 (ability to define on which page the signature is attached)
+v1.0.2
+* Workaround for issue #69 (rendering special chars as unknown char instead of just crashing. proper support/fix is still to be done)
+* Fix issue #71 (multiple PdfFileSpecification referencing the same PdfEmbeddedFileStream is now handled without crash)
+v1.0.1
+* Fixed issue #61 (XImage.PointHeight returning width)
\ No newline at end of file
diff --git a/src/foundation/src/PDFsharp/src/PdfSharp.Charting/PdfSharp.Charting.csproj b/src/foundation/src/PDFsharp/src/PdfSharp.Charting/PdfSharp.Charting.csproj
index 0cb4ed7b..cb542354 100644
--- a/src/foundation/src/PDFsharp/src/PdfSharp.Charting/PdfSharp.Charting.csproj
+++ b/src/foundation/src/PDFsharp/src/PdfSharp.Charting/PdfSharp.Charting.csproj
@@ -8,6 +8,12 @@
     <AssemblyOriginatorKeyFile>..\..\..\..\..\StrongnameKey.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
 
+  <PropertyGroup>
+    <SignAssembly>true</SignAssembly>
+    <DelaySign>false</DelaySign>
+    <AssemblyOriginatorKeyFile>..\..\..\..\..\..\StrongnameKey.snk</AssemblyOriginatorKeyFile>
+  </PropertyGroup>
+
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
   </PropertyGroup>
diff --git a/src/foundation/src/PDFsharp/src/PdfSharp/PdfSharp.csproj b/src/foundation/src/PDFsharp/src/PdfSharp/PdfSharp.csproj
index 6fb9e5af..8e7d3feb 100644
--- a/src/foundation/src/PDFsharp/src/PdfSharp/PdfSharp.csproj
+++ b/src/foundation/src/PDFsharp/src/PdfSharp/PdfSharp.csproj
@@ -11,6 +11,12 @@
     <IsAotCompatible Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net7.0'))">true</IsAotCompatible>
   </PropertyGroup>
 
+  <PropertyGroup>
+    <SignAssembly>true</SignAssembly>
+    <DelaySign>false</DelaySign>
+    <AssemblyOriginatorKeyFile>..\..\..\..\..\..\StrongnameKey.snk</AssemblyOriginatorKeyFile>
+  </PropertyGroup>
+
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
   </PropertyGroup>
diff --git a/src/foundation/src/PDFsharp/src/PdfSharp/Properties/PdfSharpProductVersionInformation.cs b/src/foundation/src/PDFsharp/src/PdfSharp/Properties/PdfSharpProductVersionInformation.cs
index d989e384..32d470eb 100644
--- a/src/foundation/src/PDFsharp/src/PdfSharp/Properties/PdfSharpProductVersionInformation.cs
+++ b/src/foundation/src/PDFsharp/src/PdfSharp/Properties/PdfSharpProductVersionInformation.cs
@@ -17,7 +17,7 @@ public static class PdfSharpProductVersionInformation
         /// <summary>
         /// The title of the product.
         /// </summary>
-        public const string Title = "PDFsharp";
+        public const string Title = "PDFsharp-extended";
 
         /// <summary>
         /// A characteristic description of the product.
diff --git a/src/foundation/src/shared/src/PdfSharp.Quality/PdfSharp.Quality.csproj b/src/foundation/src/shared/src/PdfSharp.Quality/PdfSharp.Quality.csproj
index 997f5f03..055b91ac 100644
--- a/src/foundation/src/shared/src/PdfSharp.Quality/PdfSharp.Quality.csproj
+++ b/src/foundation/src/shared/src/PdfSharp.Quality/PdfSharp.Quality.csproj
@@ -7,6 +7,12 @@
     <AssemblyOriginatorKeyFile>..\..\..\..\..\StrongnameKey.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
 
+  <PropertyGroup>
+    <SignAssembly>true</SignAssembly>
+    <DelaySign>false</DelaySign>
+    <AssemblyOriginatorKeyFile>..\..\..\..\..\..\StrongnameKey.snk</AssemblyOriginatorKeyFile>
+  </PropertyGroup>
+
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
   </PropertyGroup>
diff --git a/src/foundation/src/shared/src/PdfSharp.Snippets/PdfSharp.Snippets.csproj b/src/foundation/src/shared/src/PdfSharp.Snippets/PdfSharp.Snippets.csproj
index f43843c7..e705bb9e 100644
--- a/src/foundation/src/shared/src/PdfSharp.Snippets/PdfSharp.Snippets.csproj
+++ b/src/foundation/src/shared/src/PdfSharp.Snippets/PdfSharp.Snippets.csproj
@@ -9,6 +9,12 @@
     <AssemblyOriginatorKeyFile>..\..\..\..\..\StrongnameKey.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
 
+  <PropertyGroup>
+    <SignAssembly>true</SignAssembly>
+    <DelaySign>false</DelaySign>
+    <AssemblyOriginatorKeyFile>..\..\..\..\..\..\StrongnameKey.snk</AssemblyOriginatorKeyFile>
+  </PropertyGroup>
+
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
     <GenerateDocumentationFile>false</GenerateDocumentationFile>
   </PropertyGroup>
diff --git a/src/foundation/src/shared/src/PdfSharp.System/PdfSharp.System.csproj b/src/foundation/src/shared/src/PdfSharp.System/PdfSharp.System.csproj
index e817514b..baf02fe4 100644
--- a/src/foundation/src/shared/src/PdfSharp.System/PdfSharp.System.csproj
+++ b/src/foundation/src/shared/src/PdfSharp.System/PdfSharp.System.csproj
@@ -10,6 +10,12 @@
     <IsAotCompatible Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net7.0'))">true</IsAotCompatible>
   </PropertyGroup>
 
+  <PropertyGroup>
+    <SignAssembly>true</SignAssembly>
+    <DelaySign>false</DelaySign>
+    <AssemblyOriginatorKeyFile>..\..\..\..\..\..\StrongnameKey.snk</AssemblyOriginatorKeyFile>
+  </PropertyGroup>
+
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
   </PropertyGroup>
diff --git a/src/foundation/src/shared/src/PdfSharp.WPFonts/PdfSharp.WPFonts.csproj b/src/foundation/src/shared/src/PdfSharp.WPFonts/PdfSharp.WPFonts.csproj
index ba2d9d2f..3d4970e7 100644
--- a/src/foundation/src/shared/src/PdfSharp.WPFonts/PdfSharp.WPFonts.csproj
+++ b/src/foundation/src/shared/src/PdfSharp.WPFonts/PdfSharp.WPFonts.csproj
@@ -6,6 +6,12 @@
     <SignAssembly>True</SignAssembly>
     <AssemblyOriginatorKeyFile>..\..\..\..\..\StrongnameKey.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
+  
+  <PropertyGroup>
+    <SignAssembly>true</SignAssembly>
+    <DelaySign>false</DelaySign>
+    <AssemblyOriginatorKeyFile>..\..\..\..\..\..\StrongnameKey.snk</AssemblyOriginatorKeyFile>
+  </PropertyGroup>
 
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
     <GenerateDocumentationFile>true</GenerateDocumentationFile>