diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 923ded9..d4122d9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -2,9 +2,6 @@ name: CI
 
 on: [push, pull_request]
 
-env:
-  DOTNET_SDK_VERSION: '3.1.403'
-
 jobs:
 
   build:
@@ -14,10 +11,8 @@ jobs:
         os: [ubuntu-latest, windows-latest]
         configuration: [Debug, Release]
     steps:
-    - uses: actions/checkout@v1
-    - uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: ${{ env.DOTNET_SDK_VERSION }}
+    - uses: actions/checkout@v4
+    - uses: actions/setup-dotnet@v4
     - name: Build and test
       shell: pwsh
       run: ./build-and-test.ps1 -configuration ${{ matrix.configuration }}
@@ -27,9 +22,7 @@ jobs:
     needs: [build]
     runs-on: windows-latest
     steps:
-    - uses: actions/checkout@v1
-    - uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: ${{ env.DOTNET_SDK_VERSION }}
+    - uses: actions/checkout@v4
+    - uses: actions/setup-dotnet@v4
     - run: .\build-and-test.ps1 -configuration Release -notest
     - run: dotnet nuget push .\artifacts\packages\Release\*.nupkg -s https://api.nuget.org/v3/index.json -k ${{ secrets.NUGET_API_KEY }}
diff --git a/.vscode/tasks.json b/.vscode/tasks.json
index 335673e..7171f99 100644
--- a/.vscode/tasks.json
+++ b/.vscode/tasks.json
@@ -1,16 +1,21 @@
 {
-    "version": "0.1.0",
+    "version": "2.0.0",
     "command": "dotnet",
-    "isShellCommand": true,
     "args": [],
     "tasks": [
         {
-            "taskName": "build",
+            "label": "build",
+            "type": "shell",
+            "command": "dotnet",
             "args": [
+                "build",
                 "${workspaceRoot}/src/IxMilia.Iges.Test/IxMilia.Iges.Test.csproj"
             ],
-            "isBuildCommand": true,
-            "problemMatcher": "$msCompile"
+            "problemMatcher": "$msCompile",
+            "group": {
+                "_id": "build",
+                "isDefault": false
+            }
         }
     ]
 }
\ No newline at end of file
diff --git a/global.json b/global.json
new file mode 100644
index 0000000..8d0a1c0
--- /dev/null
+++ b/global.json
@@ -0,0 +1,6 @@
+{
+  "sdk": {
+    "version": "8.0.300",
+    "rollForward": "latestMinor"
+  }
+}
\ No newline at end of file
diff --git a/src/IxMilia.Iges.Test/IgesEntityReaderTests.cs b/src/IxMilia.Iges.Test/IgesEntityReaderTests.cs
index b223617..ee52f24 100644
--- a/src/IxMilia.Iges.Test/IgesEntityReaderTests.cs
+++ b/src/IxMilia.Iges.Test/IgesEntityReaderTests.cs
@@ -1336,7 +1336,7 @@ 208       0       0       1       0                                D      6
 ");
             Assert.Equal(new IgesPoint(1.0, 2.0, 3.0), flag.Location);
             Assert.Equal(0.1, flag.RotationAngle);
-            Assert.Equal(1, flag.Leaders.Count);
+            Assert.Single(flag.Leaders);
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.Reading)]
diff --git a/src/IxMilia.Iges.Test/IxMilia.Iges.Test.csproj b/src/IxMilia.Iges.Test/IxMilia.Iges.Test.csproj
index 0bca68b..ac3f042 100644
--- a/src/IxMilia.Iges.Test/IxMilia.Iges.Test.csproj
+++ b/src/IxMilia.Iges.Test/IxMilia.Iges.Test.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
@@ -10,13 +10,9 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.3.0" />
-    <PackageReference Include="xunit" Version="2.4.1" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <Service Include="{82a7f48d-3b50-4b1e-b82e-3ada8210c358}" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.10.0" />
+    <PackageReference Include="xunit" Version="2.9.0" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2" />
   </ItemGroup>
 
 </Project>
diff --git a/src/IxMilia.Iges/IgesFile.cs b/src/IxMilia.Iges/IgesFile.cs
index f80ed0a..7e59067 100644
--- a/src/IxMilia.Iges/IgesFile.cs
+++ b/src/IxMilia.Iges/IgesFile.cs
@@ -66,7 +66,6 @@ public IgesFile()
             Entities = new List<IgesEntity>();
         }
 
-#if HAS_FILESYSTEM_ACCESS
         public void Save(string path)
         {
             using (var stream = new FileStream(path, FileMode.Create))
@@ -74,14 +73,12 @@ public void Save(string path)
                 Save(stream);
             }
         }
-#endif
 
         public void Save(Stream stream)
         {
             new IgesFileWriter().Write(this, stream);
         }
 
-#if HAS_FILESYSTEM_ACCESS
         public static IgesFile Load(string path)
         {
             using (var stream = new FileStream(path, FileMode.Open))
@@ -89,7 +86,6 @@ public static IgesFile Load(string path)
                 return Load(stream);
             }
         }
-#endif
 
         public static IgesFile Load(Stream stream)
         {
diff --git a/src/IxMilia.Iges/IxMilia.Iges.csproj b/src/IxMilia.Iges/IxMilia.Iges.csproj
index 2334c8e..06be37e 100644
--- a/src/IxMilia.Iges/IxMilia.Iges.csproj
+++ b/src/IxMilia.Iges/IxMilia.Iges.csproj
@@ -5,7 +5,7 @@
     <Copyright>Copyright 2018</Copyright>
     <AssemblyTitle>IxMilia.Iges</AssemblyTitle>
     <Authors>IxMilia</Authors>
-    <TargetFrameworks>netstandard1.0;netstandard1.3</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0</TargetFrameworks>
     <AssemblyName>IxMilia.Iges</AssemblyName>
     <PackageId>IxMilia.Iges</PackageId>
     <PackageTags>CAD;IGES;IGS</PackageTags>
@@ -18,12 +18,8 @@
     <AllowedOutputExtensionsInPackageBuildOutputFolder>$(AllowedOutputExtensionsInPackageBuildOutputFolder);.pdb</AllowedOutputExtensionsInPackageBuildOutputFolder>
   </PropertyGroup>
 
-  <PropertyGroup Condition="'$(TargetFramework)' == 'netstandard1.3'">
-    <DefineConstants>$(DefineConstants);HAS_FILESYSTEM_ACCESS</DefineConstants>
-  </PropertyGroup>
-
   <ItemGroup>
-    <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0-beta2-19367-01" PrivateAssets="All" />
+    <PackageReference Include="Microsoft.SourceLink.GitHub" Version="8.0.0" PrivateAssets="All" />
   </ItemGroup>
 
 </Project>