diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
index 6d66e95..ccbf2b8 100644
--- a/.devcontainer/Dockerfile
+++ b/.devcontainer/Dockerfile
@@ -3,7 +3,7 @@
 # Licensed under the MIT License. See https://go.microsoft.com/fwlink/?linkid=2090316 for license information.
 #-------------------------------------------------------------------------------------------------------------
 
-FROM mcr.microsoft.com/dotnet/core/sdk:3.1
+FROM mcr.microsoft.com/dotnet/sdk:5.0
 
 # Avoid warnings by switching to noninteractive
 ENV DEBIAN_FRONTEND=noninteractive
diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
index c597fe9..1da2d78 100644
--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@@ -1,7 +1,7 @@
 // For format details, see https://aka.ms/vscode-remote/devcontainer.json or this file's README at:
 // https://github.com/microsoft/vscode-dev-containers/tree/v0.117.1/containers/dotnetcore-3.1
 {
-	"name": "C# (.NET Core 3.1)",
+	"name": "FollowingFileStream dev (.NET 5.0)",
 	"dockerFile": "Dockerfile",
 
 	// Set *default* container specific settings.json values on container create.
diff --git a/FollowingFileStream.ConsoleTestTool/FollowingFileStream.ConsoleTestTool.csproj b/FollowingFileStream.ConsoleTestTool/FollowingFileStream.ConsoleTestTool.csproj
index bb6cbce..3ac42f2 100644
--- a/FollowingFileStream.ConsoleTestTool/FollowingFileStream.ConsoleTestTool.csproj
+++ b/FollowingFileStream.ConsoleTestTool/FollowingFileStream.ConsoleTestTool.csproj
@@ -6,7 +6,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFrameworks>netcoreapp3.0;netcoreapp2.2</TargetFrameworks>
+    <TargetFrameworks>net5.0;netcoreapp3.0;netcoreapp2.2</TargetFrameworks>
     <LangVersion>8.0</LangVersion>
     <nullable>enable</nullable>
     <IsPackable>false</IsPackable>
diff --git a/FollowingFileStream.Tests/FollowingFileStream.Tests.csproj b/FollowingFileStream.Tests/FollowingFileStream.Tests.csproj
index 260b3c2..9843081 100644
--- a/FollowingFileStream.Tests/FollowingFileStream.Tests.csproj
+++ b/FollowingFileStream.Tests/FollowingFileStream.Tests.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.0;netcoreapp2.2</TargetFrameworks>
+    <TargetFrameworks>net5.0;netcoreapp3.0;netcoreapp2.2</TargetFrameworks>
     <LangVersion>8.0</LangVersion>
     <nullable>enable</nullable>
     <IsPackable>false</IsPackable>
diff --git a/FollowingFileStream/AsyncStream.cs b/FollowingFileStream/AsyncStream.cs
index 0767a5f..0a85935 100644
--- a/FollowingFileStream/AsyncStream.cs
+++ b/FollowingFileStream/AsyncStream.cs
@@ -73,7 +73,7 @@ public static AsyncStream Synchronized(AsyncStream stream)
         /// <exception cref="System.IO.IOException">
         /// An asynchronous read was attempted past the end of the file.
         /// </exception>
-        public sealed override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
+        public sealed override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback? callback, object? state)
         {
             return ApmAsyncFactory.ToBegin(
                 this.ReadAsync(buffer, offset, count, CancellationToken.None),
@@ -110,7 +110,7 @@ public sealed override IAsyncResult BeginRead(byte[] buffer, int offset, int cou
         /// <exception cref="System.IO.IOException">
         /// An asynchronous write was attempted past the end of the file.
         /// </exception>
-        public sealed override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
+        public sealed override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback? callback, object? state)
         {
             return ApmAsyncFactory.ToBegin(
                 this.WriteAsync(buffer, offset, count, CancellationToken.None),
diff --git a/FollowingFileStream/FollowingFileStream.csproj b/FollowingFileStream/FollowingFileStream.csproj
index 128a685..c3d9b88 100644
--- a/FollowingFileStream/FollowingFileStream.csproj
+++ b/FollowingFileStream/FollowingFileStream.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <OutputType>Library</OutputType>
-    <TargetFrameworks>netstandard2.1;netstandard2.0;netstandard1.3</TargetFrameworks>
+    <TargetFrameworks>net5.0;netstandard2.1;netstandard2.0;netstandard1.3</TargetFrameworks>
     <LangVersion>8.0</LangVersion>
     <nullable>enable</nullable>
     <DocumentationFile>bin\$(Configuration)\$(TargetFramework)\$(AssemblyName).xml</DocumentationFile>
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 81ddb48..180cf16 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -34,6 +34,12 @@ jobs:
       inputs:
         version: 3.x
 
+    - task: UseDotNet@2
+      displayName: 'Use dotnet sdk 5.x'
+      inputs:
+        version: 5.x
+        includePreviewVersions: true
+
     - task: GitVersion@5
       inputs:
         runtime: 'core'
@@ -45,7 +51,7 @@ jobs:
         scannerMode: 'MSBuild'
         projectKey: 'manandre_FollowingFileStream'
         projectVersion: '$(Build.BuildId)'
-        extraProperties: 'sonar.cs.opencover.reportsPaths=$(Build.SourcesDirectory)/coverage/coverage.netcoreapp3.0.opencover.xml'
+        extraProperties: 'sonar.cs.opencover.reportsPaths=$(Build.SourcesDirectory)/coverage/coverage.net5.0.opencover.xml'
 
     - task: DotNetCoreCLI@2
       displayName: Restore
@@ -80,13 +86,13 @@ jobs:
 
     - script: |
         dotnet tool install dotnet-reportgenerator-globaltool --tool-path . 
-        ./reportgenerator "-reports:$(Build.SourcesDirectory)/coverage/coverage.netcoreapp3.0.opencover.xml" "-targetdir:coverage/Cobertura" "-reporttypes:Cobertura;HTMLInline;HTMLChart"
+        ./reportgenerator "-reports:$(Build.SourcesDirectory)/coverage/coverage.net5.0.opencover.xml" "-targetdir:coverage/Cobertura" "-reporttypes:Cobertura;HTMLInline;HTMLChart"
       condition: eq( variables['Agent.OS'], 'Linux' )
       displayName: Run Reportgenerator on Linux
     
     - script: |
         dotnet tool install dotnet-reportgenerator-globaltool --tool-path .
-        .\reportgenerator.exe "-reports:$(Build.SourcesDirectory)/coverage/coverage.netcoreapp3.0.opencover.xml" "-targetdir:coverage/Cobertura" "-reporttypes:Cobertura;HTMLInline;HTMLChart"
+        .\reportgenerator.exe "-reports:$(Build.SourcesDirectory)/coverage/coverage.net5.0.opencover.xml" "-targetdir:coverage/Cobertura" "-reporttypes:Cobertura;HTMLInline;HTMLChart"
       condition: eq( variables['Agent.OS'], 'Windows_NT' )
       displayName: Run Reportgenerator on Windows
 
@@ -179,6 +185,12 @@ jobs:
         inputs:
           version: 3.x
 
+      - task: UseDotNet@2
+        displayName: 'Use dotnet sdk 5.x'
+        inputs:
+          version: 5.x
+          includePreviewVersions: true
+
       # First restore to resolve external dependencies
       - task: DotNetCoreCLI@2
         displayName: Restore