diff --git a/dotnet Community Toolkit.sln b/dotnet Community Toolkit.sln
index 6d56ee910..dc557355a 100644
--- a/dotnet Community Toolkit.sln	
+++ b/dotnet Community Toolkit.sln	
@@ -83,13 +83,13 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CommunityToolkit.Mvvm.Exter
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CommunityToolkit.Mvvm.CodeFixers.Roslyn4001", "src\CommunityToolkit.Mvvm.CodeFixers.Roslyn4001\CommunityToolkit.Mvvm.CodeFixers.Roslyn4001.csproj", "{E79DCA2A-4C59-499F-85BD-F45215ED6B72}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110", "src\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.csproj", "{FCC13AD5-CEB8-4CC1-8250-89B616D126F2}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120", "src\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.csproj", "{FCC13AD5-CEB8-4CC1-8250-89B616D126F2}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests", "tests\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests.csproj", "{C342302D-A263-42D6-B8EE-01DEF8192690}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests", "tests\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests.csproj", "{C342302D-A263-42D6-B8EE-01DEF8192690}"
 EndProject
 Project("{D954291E-2A0B-460D-934E-DC6B0785DB48}") = "CommunityToolkit.Mvvm.CodeFixers", "src\CommunityToolkit.Mvvm.CodeFixers\CommunityToolkit.Mvvm.CodeFixers.shproj", "{A2EBDA90-B720-430D-83F5-C6BCC355232C}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CommunityToolkit.Mvvm.CodeFixers.Roslyn4110", "src\CommunityToolkit.Mvvm.CodeFixers.Roslyn4110\CommunityToolkit.Mvvm.CodeFixers.Roslyn4110.csproj", "{98572004-D29A-486E-8053-6D409557CE44}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CommunityToolkit.Mvvm.CodeFixers.Roslyn4120", "src\CommunityToolkit.Mvvm.CodeFixers.Roslyn4120\CommunityToolkit.Mvvm.CodeFixers.Roslyn4120.csproj", "{98572004-D29A-486E-8053-6D409557CE44}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
diff --git a/src/CommunityToolkit.Mvvm.CodeFixers.Roslyn4110/CommunityToolkit.Mvvm.CodeFixers.Roslyn4110.csproj b/src/CommunityToolkit.Mvvm.CodeFixers.Roslyn4120/CommunityToolkit.Mvvm.CodeFixers.Roslyn4120.csproj
similarity index 100%
rename from src/CommunityToolkit.Mvvm.CodeFixers.Roslyn4110/CommunityToolkit.Mvvm.CodeFixers.Roslyn4110.csproj
rename to src/CommunityToolkit.Mvvm.CodeFixers.Roslyn4120/CommunityToolkit.Mvvm.CodeFixers.Roslyn4120.csproj
diff --git a/src/CommunityToolkit.Mvvm.CodeFixers/CommunityToolkit.Mvvm.CodeFixers.props b/src/CommunityToolkit.Mvvm.CodeFixers/CommunityToolkit.Mvvm.CodeFixers.props
index 5460cb1ea..114924f1c 100644
--- a/src/CommunityToolkit.Mvvm.CodeFixers/CommunityToolkit.Mvvm.CodeFixers.props
+++ b/src/CommunityToolkit.Mvvm.CodeFixers/CommunityToolkit.Mvvm.CodeFixers.props
@@ -26,7 +26,10 @@
 
     <!-- Also define "ROSLYN_<MAJOR>_<MINOR>_OR_GREATER" build constants, so the generator code can multi-target whenever needed and add any required polyfills -->
     <DefineConstants Condition="$([MSBuild]::VersionGreaterThanOrEquals($(MvvmToolkitSourceGeneratorRoslynVersion), 4.3.1))">$(DefineConstants);ROSLYN_4_3_1_OR_GREATER</DefineConstants>
-    <DefineConstants Condition="$([MSBuild]::VersionGreaterThanOrEquals($(MvvmToolkitSourceGeneratorRoslynVersion), 4.11.0))">$(DefineConstants);ROSLYN_4_11_0_OR_GREATER</DefineConstants>
+    <DefineConstants Condition="$([MSBuild]::VersionGreaterThanOrEquals($(MvvmToolkitSourceGeneratorRoslynVersion), 4.12.0))">$(DefineConstants);ROSLYN_4_12_0_OR_GREATER</DefineConstants>
+
+    <!-- Temporary fixup until Roslyn 4.12 ships to public NuGet -->
+    <MvvmToolkitSourceGeneratorRoslynVersion Condition="'$(MvvmToolkitSourceGeneratorRoslynVersion)' == '4.12.0'">4.12.0-3.final</MvvmToolkitSourceGeneratorRoslynVersion>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/CommunityToolkit.Mvvm.CodeFixers/UsePartialPropertyForObservablePropertyCodeFixer.cs b/src/CommunityToolkit.Mvvm.CodeFixers/UsePartialPropertyForObservablePropertyCodeFixer.cs
index 43f5ca94c..168f43b5b 100644
--- a/src/CommunityToolkit.Mvvm.CodeFixers/UsePartialPropertyForObservablePropertyCodeFixer.cs
+++ b/src/CommunityToolkit.Mvvm.CodeFixers/UsePartialPropertyForObservablePropertyCodeFixer.cs
@@ -2,7 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#if ROSLYN_4_11_0_OR_GREATER
+#if ROSLYN_4_12_0_OR_GREATER
 
 using System.Collections.Generic;
 using System.Collections.Immutable;
diff --git a/src/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.csproj b/src/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.csproj
similarity index 100%
rename from src/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.csproj
rename to src/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.csproj
diff --git a/src/CommunityToolkit.Mvvm.SourceGenerators/CommunityToolkit.Mvvm.SourceGenerators.props b/src/CommunityToolkit.Mvvm.SourceGenerators/CommunityToolkit.Mvvm.SourceGenerators.props
index 1624ac5f3..0e176df51 100644
--- a/src/CommunityToolkit.Mvvm.SourceGenerators/CommunityToolkit.Mvvm.SourceGenerators.props
+++ b/src/CommunityToolkit.Mvvm.SourceGenerators/CommunityToolkit.Mvvm.SourceGenerators.props
@@ -40,10 +40,13 @@
 
     <!-- Also define "ROSLYN_<MAJOR>_<MINOR>_OR_GREATER" build constants, so the generator code can multi-target whenever needed and add any required polyfills -->
     <DefineConstants Condition="$([MSBuild]::VersionGreaterThanOrEquals($(MvvmToolkitSourceGeneratorRoslynVersion), 4.3.1))">$(DefineConstants);ROSLYN_4_3_1_OR_GREATER</DefineConstants>
-    <DefineConstants Condition="$([MSBuild]::VersionGreaterThanOrEquals($(MvvmToolkitSourceGeneratorRoslynVersion), 4.11.0))">$(DefineConstants);ROSLYN_4_11_0_OR_GREATER</DefineConstants>
+    <DefineConstants Condition="$([MSBuild]::VersionGreaterThanOrEquals($(MvvmToolkitSourceGeneratorRoslynVersion), 4.12.0))">$(DefineConstants);ROSLYN_4_12_0_OR_GREATER</DefineConstants>
 
     <!-- Disable the removed rules analyzer for older Roslyn versions (as we might not support all diagnostics) -->
-    <NoWarn Condition="$([MSBuild]::VersionLessThan($(MvvmToolkitSourceGeneratorRoslynVersion), 4.11.0))">$(NoWarn);RS2003</NoWarn>
+    <NoWarn Condition="$([MSBuild]::VersionLessThan($(MvvmToolkitSourceGeneratorRoslynVersion), 4.12.0))">$(NoWarn);RS2003</NoWarn>
+
+    <!-- Temporary fixup until Roslyn 4.12 ships to public NuGet -->
+    <MvvmToolkitSourceGeneratorRoslynVersion Condition="'$(MvvmToolkitSourceGeneratorRoslynVersion)' == '4.12.0'">4.12.0-3.final</MvvmToolkitSourceGeneratorRoslynVersion>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservablePropertyGenerator.Execute.cs b/src/CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservablePropertyGenerator.Execute.cs
index a0a05c742..3505d05f7 100644
--- a/src/CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservablePropertyGenerator.Execute.cs
+++ b/src/CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservablePropertyGenerator.Execute.cs
@@ -98,7 +98,7 @@ public static bool IsCandidateValidForCompilation(SyntaxNode node, SemanticModel
         public static MemberDeclarationSyntax GetCandidateMemberDeclaration(SyntaxNode node)
         {
             // If the node is a property declaration, just return it directly. Note that we don't have
-            // to check whether we're using Roslyn 4.11 here, as if that's not the case all of these
+            // to check whether we're using Roslyn 4.12 here, as if that's not the case all of these
             // syntax nodes would already have pre-filtered well before this method could run at all.
             if (node is PropertyDeclarationSyntax propertySyntax)
             {
diff --git a/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/RequiresCSharpLanguageVersionPreviewAnalyzer.cs b/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/RequiresCSharpLanguageVersionPreviewAnalyzer.cs
index f0b5793b2..7cb7cd233 100644
--- a/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/RequiresCSharpLanguageVersionPreviewAnalyzer.cs
+++ b/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/RequiresCSharpLanguageVersionPreviewAnalyzer.cs
@@ -2,7 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#if ROSLYN_4_11_0_OR_GREATER
+#if ROSLYN_4_12_0_OR_GREATER
 
 using System.Collections.Immutable;
 using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
diff --git a/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/UnsupportedRoslynVersionForPartialPropertyAnalyzer.cs b/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/UnsupportedRoslynVersionForPartialPropertyAnalyzer.cs
index f33a7ad4e..29255adb5 100644
--- a/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/UnsupportedRoslynVersionForPartialPropertyAnalyzer.cs
+++ b/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/UnsupportedRoslynVersionForPartialPropertyAnalyzer.cs
@@ -2,7 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#if !ROSLYN_4_11_0_OR_GREATER
+#if !ROSLYN_4_12_0_OR_GREATER
 
 using System.Collections.Immutable;
 using System.Linq;
diff --git a/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/UseObservablePropertyOnPartialPropertyAnalyzer.cs b/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/UseObservablePropertyOnPartialPropertyAnalyzer.cs
index a4f067e5b..bbda90e1b 100644
--- a/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/UseObservablePropertyOnPartialPropertyAnalyzer.cs
+++ b/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/UseObservablePropertyOnPartialPropertyAnalyzer.cs
@@ -2,7 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#if ROSLYN_4_11_0_OR_GREATER
+#if ROSLYN_4_12_0_OR_GREATER
 
 using System.Collections.Immutable;
 using System.Linq;
diff --git a/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/WinRTGeneratedBindableCustomPropertyWithBasesMemberAnalyzer.cs b/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/WinRTGeneratedBindableCustomPropertyWithBasesMemberAnalyzer.cs
index f76cb4bc7..7e2aa7e57 100644
--- a/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/WinRTGeneratedBindableCustomPropertyWithBasesMemberAnalyzer.cs
+++ b/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/WinRTGeneratedBindableCustomPropertyWithBasesMemberAnalyzer.cs
@@ -2,7 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#if ROSLYN_4_11_0_OR_GREATER
+#if ROSLYN_4_12_0_OR_GREATER
 
 using System.Collections.Generic;
 using System.Collections.Immutable;
diff --git a/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/WinRTObservablePropertyOnFieldsIsNotAotCompatibleAnalyzer.cs b/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/WinRTObservablePropertyOnFieldsIsNotAotCompatibleAnalyzer.cs
index 0601499fd..4fa8040ba 100644
--- a/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/WinRTObservablePropertyOnFieldsIsNotAotCompatibleAnalyzer.cs
+++ b/src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/WinRTObservablePropertyOnFieldsIsNotAotCompatibleAnalyzer.cs
@@ -2,7 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#if ROSLYN_4_11_0_OR_GREATER
+#if ROSLYN_4_12_0_OR_GREATER
 
 using System.Collections.Immutable;
 using System.Linq;
diff --git a/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.SourceGenerators.targets b/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.SourceGenerators.targets
index 1106146fa..a8fce2119 100644
--- a/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.SourceGenerators.targets
+++ b/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.SourceGenerators.targets
@@ -86,7 +86,7 @@
       removes and removes all analyzers except the highest version that is supported. The fallback is just Roslyn 4.0.
     -->
     <PropertyGroup>
-      <MVVMToolkitSelectedRoslynAnalyzerDirectoryName Condition="$([MSBuild]::VersionGreaterThanOrEquals($(MVVMToolkitCurrentCompilerVersion), 4.11))">roslyn4.11</MVVMToolkitSelectedRoslynAnalyzerDirectoryName>
+      <MVVMToolkitSelectedRoslynAnalyzerDirectoryName Condition="$([MSBuild]::VersionGreaterThanOrEquals($(MVVMToolkitCurrentCompilerVersion), 4.12))">roslyn4.12</MVVMToolkitSelectedRoslynAnalyzerDirectoryName>
       <MVVMToolkitSelectedRoslynAnalyzerDirectoryName Condition="$([MSBuild]::VersionGreaterThanOrEquals($(MVVMToolkitCurrentCompilerVersion), 4.3))">roslyn4.3</MVVMToolkitSelectedRoslynAnalyzerDirectoryName>
       <MVVMToolkitSelectedRoslynAnalyzerDirectoryName Condition="'$(MVVMToolkitSelectedRoslynAnalyzerDirectoryName)' == ''">roslyn4.0</MVVMToolkitSelectedRoslynAnalyzerDirectoryName>
     </PropertyGroup>
diff --git a/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.csproj b/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.csproj
index 522b215a5..69a5befaf 100644
--- a/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.csproj
+++ b/src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.csproj
@@ -68,9 +68,9 @@
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <ProjectReference Include="..\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4001\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4001.csproj" ReferenceOutputAssembly="false" />
     <ProjectReference Include="..\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4031\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4031.csproj" ReferenceOutputAssembly="false" />
-    <ProjectReference Include="..\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.csproj" ReferenceOutputAssembly="false" />
+    <ProjectReference Include="..\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.csproj" ReferenceOutputAssembly="false" />
     <ProjectReference Include="..\CommunityToolkit.Mvvm.CodeFixers.Roslyn4001\CommunityToolkit.Mvvm.CodeFixers.Roslyn4001.csproj" ReferenceOutputAssembly="false" />
-    <ProjectReference Include="..\CommunityToolkit.Mvvm.CodeFixers.Roslyn4110\CommunityToolkit.Mvvm.CodeFixers.Roslyn4110.csproj" ReferenceOutputAssembly="false" />
+    <ProjectReference Include="..\CommunityToolkit.Mvvm.CodeFixers.Roslyn4120\CommunityToolkit.Mvvm.CodeFixers.Roslyn4120.csproj" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
   <!-- Add the [InternalsVisibleTo] attribute for the test project -->
@@ -122,10 +122,10 @@
     -->
     <None Include="..\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4001\bin\$(Configuration)\netstandard2.0\CommunityToolkit.Mvvm.SourceGenerators.dll" PackagePath="analyzers\dotnet\roslyn4.0\cs" Pack="true" Visible="false" />
     <None Include="..\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4031\bin\$(Configuration)\netstandard2.0\CommunityToolkit.Mvvm.SourceGenerators.dll" PackagePath="analyzers\dotnet\roslyn4.3\cs" Pack="true" Visible="false" />
-    <None Include="..\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110\bin\$(Configuration)\netstandard2.0\CommunityToolkit.Mvvm.SourceGenerators.dll" PackagePath="analyzers\dotnet\roslyn4.11\cs" Pack="true" Visible="false" />
+    <None Include="..\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120\bin\$(Configuration)\netstandard2.0\CommunityToolkit.Mvvm.SourceGenerators.dll" PackagePath="analyzers\dotnet\roslyn4.12\cs" Pack="true" Visible="false" />
     <None Include="..\CommunityToolkit.Mvvm.CodeFixers.Roslyn4001\bin\$(Configuration)\netstandard2.0\CommunityToolkit.Mvvm.CodeFixers.dll" PackagePath="analyzers\dotnet\roslyn4.0\cs" Pack="true" Visible="false" />
     <None Include="..\CommunityToolkit.Mvvm.CodeFixers.Roslyn4001\bin\$(Configuration)\netstandard2.0\CommunityToolkit.Mvvm.CodeFixers.dll" PackagePath="analyzers\dotnet\roslyn4.3\cs" Pack="true" Visible="false" />
-    <None Include="..\CommunityToolkit.Mvvm.CodeFixers.Roslyn4110\bin\$(Configuration)\netstandard2.0\CommunityToolkit.Mvvm.CodeFixers.dll" PackagePath="analyzers\dotnet\roslyn4.11\cs" Pack="true" Visible="false" />
+    <None Include="..\CommunityToolkit.Mvvm.CodeFixers.Roslyn4120\bin\$(Configuration)\netstandard2.0\CommunityToolkit.Mvvm.CodeFixers.dll" PackagePath="analyzers\dotnet\roslyn4.12\cs" Pack="true" Visible="false" />
   </ItemGroup>
 
 </Project>
\ No newline at end of file
diff --git a/tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests.csproj b/tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests.csproj
similarity index 82%
rename from tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests.csproj
rename to tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests.csproj
index a6b432501..eba477975 100644
--- a/tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests.csproj
+++ b/tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests.csproj
@@ -2,13 +2,13 @@
 
   <PropertyGroup>
     <TargetFrameworks>net472;net7.0;net8.0</TargetFrameworks>
-    <DefineConstants>$(DefineConstants);ROSLYN_4_3_1_OR_GREATER;ROSLYN_4_11_0_OR_GREATER</DefineConstants>
+    <DefineConstants>$(DefineConstants);ROSLYN_4_3_1_OR_GREATER;ROSLYN_4_12_0_OR_GREATER</DefineConstants>
   </PropertyGroup>
 
   <ItemGroup>
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Analyzer.Testing" Version="1.1.2" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.CodeFix.Testing" Version="1.1.2" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.11.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.12.0-3.final" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
     <PackageReference Include="MSTest.TestAdapter" Version="3.6.1" />
     <PackageReference Include="MSTest.TestFramework" Version="3.6.1" />
@@ -16,8 +16,8 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\CommunityToolkit.Mvvm\CommunityToolkit.Mvvm.csproj" />
-    <ProjectReference Include="..\..\src\CommunityToolkit.Mvvm.CodeFixers.Roslyn4110\CommunityToolkit.Mvvm.CodeFixers.Roslyn4110.csproj" />
-    <ProjectReference Include="..\..\src\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.csproj" />
+    <ProjectReference Include="..\..\src\CommunityToolkit.Mvvm.CodeFixers.Roslyn4120\CommunityToolkit.Mvvm.CodeFixers.Roslyn4120.csproj" />
+    <ProjectReference Include="..\..\src\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120\CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.csproj" />
   </ItemGroup>
 
   <Import Project="..\CommunityToolkit.Mvvm.SourceGenerators.UnitTests\CommunityToolkit.Mvvm.SourceGenerators.UnitTests.projitems" Label="Shared" />
diff --git a/tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests/Test_SourceGeneratorsCodegen.cs b/tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests/Test_SourceGeneratorsCodegen.cs
similarity index 100%
rename from tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests/Test_SourceGeneratorsCodegen.cs
rename to tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests/Test_SourceGeneratorsCodegen.cs
diff --git a/tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests/Test_SourceGeneratorsDiagnostics.cs b/tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests/Test_SourceGeneratorsDiagnostics.cs
similarity index 96%
rename from tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests/Test_SourceGeneratorsDiagnostics.cs
rename to tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests/Test_SourceGeneratorsDiagnostics.cs
index d1f55ddc1..0cadc6439 100644
--- a/tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests/Test_SourceGeneratorsDiagnostics.cs
+++ b/tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests/Test_SourceGeneratorsDiagnostics.cs
@@ -32,7 +32,7 @@ public partial class SampleViewModel : ObservableObject
     }
 
     [TestMethod]
-    public async Task RequireCSharpLanguageVersionPreviewAnalyzer_LanguageVersionIsNotPreview_Partial_Warns()
+    public async Task RequireCSharpLanguageVersionPreviewAnalyzer_LanguageVersionIsNotPreview_CSharp12_Partial_Warns()
     {
         const string source = """
             using CommunityToolkit.Mvvm.ComponentModel;
@@ -51,8 +51,32 @@ await CSharpAnalyzerWithLanguageVersionTest<RequiresCSharpLanguageVersionPreview
             source,
             LanguageVersion.CSharp12,
 
-            // /0/Test0.cs(8,31): error CS8703: The modifier 'partial' is not valid for this item in C# 12.0. Please use language version 'preview' or greater.
-            DiagnosticResult.CompilerError("CS8703").WithSpan(8, 31, 8, 35).WithArguments("partial", "12.0", "preview"),
+            // /0/Test0.cs(8,31): error CS8703: The modifier 'partial' is not valid for this item in C# 12.0. Please use language version '13.0' or greater.
+            DiagnosticResult.CompilerError("CS8703").WithSpan(8, 31, 8, 35).WithArguments("partial", "12.0", "13.0"),
+            // /0/Test0.cs(8,31): error CS9248: Partial property 'SampleViewModel.Name' must have an implementation part.
+            DiagnosticResult.CompilerError("CS9248").WithSpan(8, 31, 8, 35).WithArguments("MyApp.SampleViewModel.Name"));
+    }
+
+    [TestMethod]
+    public async Task RequireCSharpLanguageVersionPreviewAnalyzer_LanguageVersionIsNotPreview_CSharp13_Partial_Warns()
+    {
+        const string source = """
+            using CommunityToolkit.Mvvm.ComponentModel;
+            
+            namespace MyApp
+            {
+                public partial class SampleViewModel : ObservableObject
+                {            
+                    [{|MVVMTK0041:ObservableProperty|}]            
+                    public partial string Name { get; set; }
+                }
+            }
+            """;
+
+        await CSharpAnalyzerWithLanguageVersionTest<RequiresCSharpLanguageVersionPreviewAnalyzer>.VerifyAnalyzerAsync(
+            source,
+            LanguageVersion.CSharp13,
+
             // /0/Test0.cs(8,31): error CS9248: Partial property 'SampleViewModel.Name' must have an implementation part.
             DiagnosticResult.CompilerError("CS9248").WithSpan(8, 31, 8, 35).WithArguments("MyApp.SampleViewModel.Name"));
     }
diff --git a/tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests/Test_UsePartialPropertyForObservablePropertyCodeFixer.cs b/tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests/Test_UsePartialPropertyForObservablePropertyCodeFixer.cs
similarity index 100%
rename from tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4110.UnitTests/Test_UsePartialPropertyForObservablePropertyCodeFixer.cs
rename to tests/CommunityToolkit.Mvvm.SourceGenerators.Roslyn4120.UnitTests/Test_UsePartialPropertyForObservablePropertyCodeFixer.cs