diff --git a/source/AutomationTest/AvalonDockTest/AvalonDockTest.csproj b/source/AutomationTest/AvalonDockTest/AvalonDockTest.csproj
index bca5175b..83aed9ab 100644
--- a/source/AutomationTest/AvalonDockTest/AvalonDockTest.csproj
+++ b/source/AutomationTest/AvalonDockTest/AvalonDockTest.csproj
@@ -1,7 +1,7 @@
-<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
+<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
 
   <PropertyGroup>
-    <TargetFrameworks>net5.0-windows;net452</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.0;net5.0-windows;net452</TargetFrameworks>
     <ProjectGuid>{FE4E16A2-876A-4356-9974-8A89C50B2A5A}</ProjectGuid>
     <RootNamespace>AvalonDockTest</RootNamespace>
     <AssemblyName>AvalonDockTest</AssemblyName>
diff --git a/source/CaliburnDockTestApp/CaliburnDockTestApp.csproj b/source/CaliburnDockTestApp/CaliburnDockTestApp.csproj
index 69bf10fc..55a9d0a0 100644
--- a/source/CaliburnDockTestApp/CaliburnDockTestApp.csproj
+++ b/source/CaliburnDockTestApp/CaliburnDockTestApp.csproj
@@ -1,8 +1,8 @@
-<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
+<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
 
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
-    <TargetFrameworks>net5.0-windows;net4.5.2</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.0;net5.0-windows;net452</TargetFrameworks>
     <UseWPF>true</UseWPF>
   </PropertyGroup>
 
diff --git a/source/Components/AvalonDock.Themes.Aero/AvalonDock.Themes.Aero.csproj b/source/Components/AvalonDock.Themes.Aero/AvalonDock.Themes.Aero.csproj
index f92cb6d9..809d8688 100644
--- a/source/Components/AvalonDock.Themes.Aero/AvalonDock.Themes.Aero.csproj
+++ b/source/Components/AvalonDock.Themes.Aero/AvalonDock.Themes.Aero.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
   <PropertyGroup>
     <RootNamespace>AvalonDock.Themes</RootNamespace>
-    <TargetFrameworks>net5.0-windows;net4</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.0;net5.0-windows;net40</TargetFrameworks>
     <UseWPF>true</UseWPF>
     <AssemblyOriginatorKeyFile>sn.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
diff --git a/source/Components/AvalonDock.Themes.Expression/AvalonDock.Themes.Expression.csproj b/source/Components/AvalonDock.Themes.Expression/AvalonDock.Themes.Expression.csproj
index d7e59711..996a6b44 100644
--- a/source/Components/AvalonDock.Themes.Expression/AvalonDock.Themes.Expression.csproj
+++ b/source/Components/AvalonDock.Themes.Expression/AvalonDock.Themes.Expression.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
   <PropertyGroup>
     <RootNamespace>AvalonDock.Themes</RootNamespace>
-    <TargetFrameworks>net5.0-windows;net4</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.0;net5.0-windows;net40</TargetFrameworks>
     <UseWPF>true</UseWPF>
     <AssemblyOriginatorKeyFile>sn.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
diff --git a/source/Components/AvalonDock.Themes.Metro/AvalonDock.Themes.Metro.csproj b/source/Components/AvalonDock.Themes.Metro/AvalonDock.Themes.Metro.csproj
index d1799bf2..5138c7bc 100644
--- a/source/Components/AvalonDock.Themes.Metro/AvalonDock.Themes.Metro.csproj
+++ b/source/Components/AvalonDock.Themes.Metro/AvalonDock.Themes.Metro.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
   <PropertyGroup>
     <RootNamespace>AvalonDock.Themes</RootNamespace>
-    <TargetFrameworks>net5.0-windows;net4</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.0;net5.0-windows;net40</TargetFrameworks>
     <UseWPF>true</UseWPF>
     <AssemblyOriginatorKeyFile>sn.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
@@ -19,7 +19,7 @@
     <Authors>https://github.com/Dirkster99/AvalonDock</Authors>
     <PackageLicenseFile>LICENSE</PackageLicenseFile>
   </PropertyGroup>
-  
+
   <ItemGroup>
     <Resource Include="**\*.png" />
   </ItemGroup>
diff --git a/source/Components/AvalonDock.Themes.VS2010/AvalonDock.Themes.VS2010.csproj b/source/Components/AvalonDock.Themes.VS2010/AvalonDock.Themes.VS2010.csproj
index 1afd3338..6c9c0d2c 100644
--- a/source/Components/AvalonDock.Themes.VS2010/AvalonDock.Themes.VS2010.csproj
+++ b/source/Components/AvalonDock.Themes.VS2010/AvalonDock.Themes.VS2010.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
   <PropertyGroup>
     <RootNamespace>AvalonDock.Themes</RootNamespace>
-    <TargetFrameworks>net5.0-windows;net4</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.0;net5.0-windows;net40</TargetFrameworks>
     <UseWPF>true</UseWPF>
     <AssemblyOriginatorKeyFile>sn.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
diff --git a/source/Components/AvalonDock.Themes.VS2013/AvalonDock.Themes.VS2013.csproj b/source/Components/AvalonDock.Themes.VS2013/AvalonDock.Themes.VS2013.csproj
index c96db58f..df82dad8 100644
--- a/source/Components/AvalonDock.Themes.VS2013/AvalonDock.Themes.VS2013.csproj
+++ b/source/Components/AvalonDock.Themes.VS2013/AvalonDock.Themes.VS2013.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
   <PropertyGroup>
     <RootNamespace>AvalonDock.Themes</RootNamespace>
-    <TargetFrameworks>net5.0-windows;net4</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.0;net5.0-windows;net40</TargetFrameworks>
     <UseWPF>true</UseWPF>
     <AssemblyOriginatorKeyFile>sn.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
diff --git a/source/Components/AvalonDock/AvalonDock.csproj b/source/Components/AvalonDock/AvalonDock.csproj
index c7c942d7..8390ca00 100644
--- a/source/Components/AvalonDock/AvalonDock.csproj
+++ b/source/Components/AvalonDock/AvalonDock.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
   <PropertyGroup>
     <RootNamespace>AvalonDock</RootNamespace>
-    <TargetFrameworks>net5.0-windows;net4</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.0;net5.0-windows;net40</TargetFrameworks>
     <UseWPF>true</UseWPF>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>sn.snk</AssemblyOriginatorKeyFile>
diff --git a/source/MLibTest/MLibTest/MLibTest.csproj b/source/MLibTest/MLibTest/MLibTest.csproj
index 68636244..865d89a0 100644
--- a/source/MLibTest/MLibTest/MLibTest.csproj
+++ b/source/MLibTest/MLibTest/MLibTest.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
-    <TargetFrameworks>net5.0-windows;net4.5.2</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.0;net5.0-windows;net452</TargetFrameworks>
     <UseWPF>true</UseWPF>
   </PropertyGroup>
 
@@ -21,6 +21,12 @@
     </PackageReference>
   </ItemGroup>
 
+	<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0'">
+		<PackageReference Include="Microsoft.Xaml.Behaviors.Wpf">
+			<Version>1.1.19</Version>
+		</PackageReference>
+	</ItemGroup>
+
   <ItemGroup>
     <PackageReference Include="Dirkster.ColorPickerLib" Version="1.6.0" />
     <PackageReference Include="Dirkster.MLib" Version="1.3.1.2" />
diff --git a/source/MLibTest/MLibTest_Components/ServiceLocator/ServiceLocator.csproj b/source/MLibTest/MLibTest_Components/ServiceLocator/ServiceLocator.csproj
index 908108cd..df8ec47c 100644
--- a/source/MLibTest/MLibTest_Components/ServiceLocator/ServiceLocator.csproj
+++ b/source/MLibTest/MLibTest_Components/ServiceLocator/ServiceLocator.csproj
@@ -1,7 +1,7 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net5.0;net4.5</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.0;net5.0;net45</TargetFrameworks>
   </PropertyGroup>
 
 </Project>
diff --git a/source/MLibTest/MLibTest_Components/Settings/SettingsModel/SettingsModel.csproj b/source/MLibTest/MLibTest_Components/Settings/SettingsModel/SettingsModel.csproj
index 80769345..c81af4f4 100644
--- a/source/MLibTest/MLibTest_Components/Settings/SettingsModel/SettingsModel.csproj
+++ b/source/MLibTest/MLibTest_Components/Settings/SettingsModel/SettingsModel.csproj
@@ -1,7 +1,7 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net5.0;net4.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;net40</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net5.0'">
@@ -10,7 +10,13 @@
     </PackageReference>
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetFramework)' == 'net4.0'">
+	<ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
+		<PackageReference Include="System.Security.Cryptography.ProtectedData">
+			<Version>4.6.0</Version>
+		</PackageReference>
+	</ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'net40'">
     <Reference Include="System.Security"/>
   </ItemGroup>
 
diff --git a/source/MVVMTestApp/MVVMTestApp.csproj b/source/MVVMTestApp/MVVMTestApp.csproj
index 3898ca5f..79c5b073 100644
--- a/source/MVVMTestApp/MVVMTestApp.csproj
+++ b/source/MVVMTestApp/MVVMTestApp.csproj
@@ -1,8 +1,8 @@
-<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
+<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
 
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
-    <TargetFrameworks>net5.0-windows;net4</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.0;net5.0-windows;net40</TargetFrameworks>
     <UseWPF>true</UseWPF>
   </PropertyGroup>
 
diff --git a/source/TestApp/TestApp.csproj b/source/TestApp/TestApp.csproj
index 9b0413d8..95ac2e62 100644
--- a/source/TestApp/TestApp.csproj
+++ b/source/TestApp/TestApp.csproj
@@ -1,7 +1,7 @@
-<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
+<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
     <PropertyGroup>
         <RootNamespace>TestApp</RootNamespace>
-        <TargetFrameworks>net5.0-windows;net40</TargetFrameworks>
+        <TargetFrameworks>netcoreapp3.0;net5.0-windows;net40</TargetFrameworks>
         <UseWPF>true</UseWPF>
         <UseWindowsForms>true</UseWindowsForms>
         <ApplicationIcon />
diff --git a/source/WinFormsTestApp/WinFormsTestApp.csproj b/source/WinFormsTestApp/WinFormsTestApp.csproj
index 21ff85f8..05171c25 100644
--- a/source/WinFormsTestApp/WinFormsTestApp.csproj
+++ b/source/WinFormsTestApp/WinFormsTestApp.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
-    <TargetFrameworks>net5.0-windows;net4.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.0;net5.0-windows;net40</TargetFrameworks>
     <UseWindowsForms>true</UseWindowsForms>
     <UseWPF>true</UseWPF>
     <StartupObject>AvalonDock.WinFormsTestApp.Program</StartupObject>