diff --git a/.github/workflows/csharp.yml b/.github/workflows/csharp.yml
index a5b414d..48657b6 100644
--- a/.github/workflows/csharp.yml
+++ b/.github/workflows/csharp.yml
@@ -24,7 +24,7 @@ jobs:
         with:
           dotnet-version: '8.0.x'
 
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
         with:
           submodules: true
       - name: Test
@@ -39,7 +39,7 @@ jobs:
         with:
           dotnet-version: '8.0.x'
 
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
         with:
           submodules: true
       - name: Publish NuGet package to GitHub Package Registry
@@ -48,7 +48,7 @@ jobs:
           dotnet pack -c Release --include-symbols
           dotnet nuget add source https://nuget.pkg.github.com/linksplatform/index.json --name GitHub --username linksplatform --password ${{ secrets.GITHUB_TOKEN }} --store-password-in-clear-text
           dotnet nuget push **/*.nupkg --source GitHub --skip-duplicate
-  pusnToNuget:
+  pushToNuget:
     runs-on: ubuntu-latest
     needs: test
     steps:
@@ -57,7 +57,7 @@ jobs:
         with:
           dotnet-version: '8.0.x'
 
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
         with:
           submodules: true
       - name: Read project information
@@ -70,7 +70,7 @@ jobs:
           export REPOSITORY_NAME=$(basename ${{ github.repository }})
           wget "$SCRIPTS_BASE_URL/push-csharp-nuget.sh"
           bash ./push-csharp-nuget.sh
-  publiseRelease:
+  publishRelease:
     runs-on: ubuntu-latest
     needs: test
     steps:
@@ -79,7 +79,7 @@ jobs:
         with:
           dotnet-version: '8.0.x'
 
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
         with:
           submodules: true
       - name: Read project information
@@ -106,7 +106,7 @@ jobs:
         with:
           dotnet-version: '8.0.x'
 
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - name: Get changed files using defaults
@@ -124,7 +124,7 @@ jobs:
               isCsFilesChanged='true'
             fi
           done
-          echo "::set-output name=isCsFilesChanged::${isCsFilesChanged}"
+          echo "isCsFilesChanged=${isCsFilesChanged}" >> $GITHUB_OUTPUT
           echo "isCsFilesChanged: ${isCsFilesChanged}"
   generatePdfWithCode:
     runs-on: ubuntu-latest
@@ -136,7 +136,7 @@ jobs:
         with:
           dotnet-version: '8.0.x'
 
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
         with:
           submodules: true
       - name: Generate PDF with code
@@ -156,7 +156,7 @@ jobs:
         with:
           dotnet-version: '8.0.x'
 
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
         with:
           submodules: true
       - name: Publish documentation to gh-pages branch
diff --git a/csharp/Platform.Interfaces.Tests/InterfacesTests.cs b/csharp/Platform.Interfaces.Tests/InterfacesTests.cs
index ecd9b4d..28739cd 100644
--- a/csharp/Platform.Interfaces.Tests/InterfacesTests.cs
+++ b/csharp/Platform.Interfaces.Tests/InterfacesTests.cs
@@ -10,16 +10,16 @@ public static class InterfacesTests
         [Fact]
         public static void BuildTest()
         {
-            ICounter<int, int> c1 = null;
-            ICounter<int> c2 = null;
-            ICriterionMatcher<int> cm1 = null;
-            IFactory<int> f1 = null;
-            IProperties<int, int, int> p1 = null;
-            IProperty<int, int> p2 = null;
-            IProvider<int, int> p3 = null;
-            IProvider<int> p4 = null;
-            ISetter<int, int> s1 = null;
-            ISetter<int> s2 = null;
+            ICounter<int, int>? c1 = null;
+            ICounter<int>? c2 = null;
+            ICriterionMatcher<int>? cm1 = null;
+            IFactory<int>? f1 = null;
+            IProperties<int, int, int>? p1 = null;
+            IProperty<int, int>? p2 = null;
+            IProvider<int, int>? p3 = null;
+            IProvider<int>? p4 = null;
+            ISetter<int, int>? s1 = null;
+            ISetter<int>? s2 = null;
         }
     }
 }
diff --git a/csharp/Platform.Interfaces/Platform.Interfaces.csproj b/csharp/Platform.Interfaces/Platform.Interfaces.csproj
index e420800..e453e5a 100644
--- a/csharp/Platform.Interfaces/Platform.Interfaces.csproj
+++ b/csharp/Platform.Interfaces/Platform.Interfaces.csproj
@@ -10,7 +10,7 @@
     <AssemblyName>Platform.Interfaces</AssemblyName>
     <PackageId>Platform.Interfaces</PackageId>
     <PackageTags>LinksPlatform;Interfaces;ICounter;ICriterionMatcher;IFactory;IProperties;IProperty;IProvider;ISetter</PackageTags>
-    <PackageIconUrl>https://raw.githubusercontent.com/linksplatform/Documentation/18469f4d033ee9a5b7b84caab9c585acab2ac519/doc/Avatar-rainbow-icon-64x64.png</PackageIconUrl>
+    <PackageIcon>icon.png</PackageIcon>
     <PackageProjectUrl>https://linksplatform.github.io/Interfaces</PackageProjectUrl>
     <PackageLicenseExpression>Unlicense</PackageLicenseExpression>
     <RepositoryType>git</RepositoryType>
@@ -36,4 +36,8 @@
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="All" />
   </ItemGroup>
 
+  <ItemGroup>
+    <None Include="icon.png" Pack="true" PackagePath="\" />
+  </ItemGroup>
+
 </Project>
diff --git a/csharp/Platform.Interfaces/icon.png b/csharp/Platform.Interfaces/icon.png
new file mode 100644
index 0000000..c1ad0ca
Binary files /dev/null and b/csharp/Platform.Interfaces/icon.png differ