diff --git a/ILSpy.BamlDecompiler/ILSpy.BamlDecompiler.csproj b/ILSpy.BamlDecompiler/ILSpy.BamlDecompiler.csproj
index d501102bd..764156382 100644
--- a/ILSpy.BamlDecompiler/ILSpy.BamlDecompiler.csproj
+++ b/ILSpy.BamlDecompiler/ILSpy.BamlDecompiler.csproj
@@ -39,7 +39,7 @@
 
   <ItemGroup>
     <PackageReference Include="AvalonEdit" Version="$(AvalonEditVersion)" />
-    <PackageReference Include="System.Composition" Version="1.3.0" />
+    <PackageReference Include="System.Composition" Version="$(SystemCompositionVersion)" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/ILSpy/Docking/DockLayoutSettings.cs b/ILSpy/Docking/DockLayoutSettings.cs
index 132e5390d..fc776db79 100644
--- a/ILSpy/Docking/DockLayoutSettings.cs
+++ b/ILSpy/Docking/DockLayoutSettings.cs
@@ -22,7 +22,7 @@ using System.Linq;
 using System.Xml;
 using System.Xml.Linq;
 
-using Xceed.Wpf.AvalonDock.Layout.Serialization;
+using AvalonDock.Layout.Serialization;
 
 namespace ICSharpCode.ILSpy.Docking
 {
diff --git a/ILSpy/Docking/DockWorkspace.cs b/ILSpy/Docking/DockWorkspace.cs
index 35e3d6c65..790dbdad2 100644
--- a/ILSpy/Docking/DockWorkspace.cs
+++ b/ILSpy/Docking/DockWorkspace.cs
@@ -29,13 +29,14 @@ using System.Threading.Tasks;
 using System.Windows.Navigation;
 using System.Windows.Threading;
 
+using AvalonDock;
+using AvalonDock.Layout;
+using AvalonDock.Layout.Serialization;
+
 using ICSharpCode.AvalonEdit.Highlighting;
 using ICSharpCode.ILSpy.TextView;
 using ICSharpCode.ILSpy.ViewModels;
 
-using Xceed.Wpf.AvalonDock.Layout;
-using Xceed.Wpf.AvalonDock.Layout.Serialization;
-
 namespace ICSharpCode.ILSpy.Docking
 {
 	public class DockWorkspace : INotifyPropertyChanged, ILayoutUpdateStrategy
@@ -109,7 +110,7 @@ namespace ICSharpCode.ILSpy.Docking
 			}
 		}
 
-		public void InitializeLayout(Xceed.Wpf.AvalonDock.DockingManager manager)
+		public void InitializeLayout(DockingManager manager)
 		{
 			manager.LayoutUpdateStrategy = this;
 			XmlLayoutSerializer serializer = new XmlLayoutSerializer(manager);
diff --git a/ILSpy/ILSpy.csproj b/ILSpy/ILSpy.csproj
index c150d99b5..05e6a8c8d 100644
--- a/ILSpy/ILSpy.csproj
+++ b/ILSpy/ILSpy.csproj
@@ -54,13 +54,13 @@
     <PackageReference Include="AvalonEdit" Version="$(AvalonEditVersion)" />
     <PackageReference Include="System.Reflection.Metadata" Version="$(SystemReflectionMetadataVersion)" />
     <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="$(SystemCompilerServicesUnsafeVersion)" />
-    <PackageReference Include="Dirkster.AvalonDock" Version="3.6.1" />
+    <PackageReference Include="Dirkster.AvalonDock" Version="4.50.1" />
     <PackageReference Include="Microsoft.VisualStudio.Composition" Version="16.9.6-alpha" />
-    <PackageReference Include="System.Composition" Version="1.3.0" />
+    <PackageReference Include="System.Composition" Version="$(SystemCompositionVersion)" />
     <PackageReference Include="Mono.Cecil" Version="$(MonoCecilVersion)" />
-    <PackageReference Include="OSVersionHelper" Version="1.0.11" />
-    <PackageReference Include="DataGridExtensions" Version="2.1.1" />
-    <PackageReference Include="Microsoft.Xaml.Behaviors.Wpf" Version="1.1.19" />
+    <PackageReference Include="OSVersionHelper" Version="1.1.24" />
+    <PackageReference Include="DataGridExtensions" Version="2.5.0" />
+    <PackageReference Include="Microsoft.Xaml.Behaviors.Wpf" Version="1.1.31" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/ILSpy/MainWindow.xaml b/ILSpy/MainWindow.xaml
index 479293aa4..8ec900c3b 100644
--- a/ILSpy/MainWindow.xaml
+++ b/ILSpy/MainWindow.xaml
@@ -4,7 +4,7 @@
 	x:ClassModifier="public"
 	xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:tv="clr-namespace:ICSharpCode.TreeView;assembly=ICSharpCode.TreeView"
 	xmlns:local="clr-namespace:ICSharpCode.ILSpy"
-	xmlns:avalondock="http://schemas.xceed.com/wpf/xaml/avalondock"
+	xmlns:avalondock="https://github.com/Dirkster99/AvalonDock"
 	xmlns:controls="clr-namespace:ICSharpCode.ILSpy.Controls"
 	xmlns:docking="clr-namespace:ICSharpCode.ILSpy.Docking"
 	xmlns:textview="clr-namespace:ICSharpCode.ILSpy.TextView"
diff --git a/ILSpy/MainWindow.xaml.cs b/ILSpy/MainWindow.xaml.cs
index 5622f0f50..8ac8d7b93 100644
--- a/ILSpy/MainWindow.xaml.cs
+++ b/ILSpy/MainWindow.xaml.cs
@@ -36,6 +36,8 @@ using System.Windows.Media.Imaging;
 using System.Windows.Navigation;
 using System.Windows.Threading;
 
+using AvalonDock.Layout.Serialization;
+
 using ICSharpCode.Decompiler;
 using ICSharpCode.Decompiler.Documentation;
 using ICSharpCode.Decompiler.Metadata;
@@ -52,8 +54,6 @@ using Microsoft.Win32;
 
 using OSVersionHelper;
 
-using Xceed.Wpf.AvalonDock.Layout.Serialization;
-
 namespace ICSharpCode.ILSpy
 {
 	class MainWindowDataContext
diff --git a/TestPlugin/Properties/launchSettings.json b/TestPlugin/Properties/launchSettings.json
index 3578e8aa6..e969a0da9 100644
--- a/TestPlugin/Properties/launchSettings.json
+++ b/TestPlugin/Properties/launchSettings.json
@@ -2,7 +2,7 @@
   "profiles": {
     "TestPlugin": {
       "commandName": "Executable",
-      "executablePath": "$(OutDir)ILSpy.exe",
+      "executablePath": ".\\ILSpy.exe",
       "commandLineArgs": "/separate"
     }
   }
diff --git a/packages.props b/packages.props
index ba04357e8..92e9c414c 100644
--- a/packages.props
+++ b/packages.props
@@ -8,9 +8,10 @@
 		<SystemCollectionsImmutableVersion>5.0.0</SystemCollectionsImmutableVersion>
 		<SystemReflectionMetadataVersion>5.0.0</SystemReflectionMetadataVersion>
 		<SystemCompilerServicesUnsafeVersion>5.0.0</SystemCompilerServicesUnsafeVersion>
+		<SystemCompositionVersion>5.0.1</SystemCompositionVersion>
 		<ILAsmVersion>5.0.0</ILAsmVersion> <!-- Microsoft.NETCore.ILAsm -->
 		<RoslynVersion>3.8.0</RoslynVersion> <!-- Microsoft.CodeAnalysis.* -->
-		<MonoCecilVersion>0.10.3</MonoCecilVersion>
+		<MonoCecilVersion>0.11.3</MonoCecilVersion>
 		<AvalonEditVersion>6.1.0-preview1</AvalonEditVersion>
 		<NUnitVersion>3.12.0</NUnitVersion>
 		<NUnitAdapterVersion>3.13.0</NUnitAdapterVersion>