diff --git a/src/Directory.Build.props b/src/Directory.Build.props
index 5e3ad489a..bcf444c75 100644
--- a/src/Directory.Build.props
+++ b/src/Directory.Build.props
@@ -23,8 +23,7 @@
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(Configuration)' == 'Release'">
-<!-- TODO: re-enable when all Obsolete warnings are fixed -->
-<!--    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>-->
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/ImageSharp/ImageSharp.csproj b/src/ImageSharp/ImageSharp.csproj
index 0d803475a..be0e9032b 100644
--- a/src/ImageSharp/ImageSharp.csproj
+++ b/src/ImageSharp/ImageSharp.csproj
@@ -10,8 +10,7 @@
     <VersionPrefix Condition="$(packageversion) != ''">$(packageversion)</VersionPrefix>
     <VersionPrefix Condition="$(packageversion) == ''">0.0.1</VersionPrefix>
 
-<!--    <TargetFrameworks>netcoreapp3.1;netcoreapp2.1;netstandard2.1;netstandard2.0;netstandard1.3;net472</TargetFrameworks>-->
-    <TargetFrameworks>netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;netcoreapp2.1;netstandard2.1;netstandard2.0;netstandard1.3;net472</TargetFrameworks>
 
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
diff --git a/src/ImageSharp/Memory/Buffer2DExtensions.cs b/src/ImageSharp/Memory/Buffer2DExtensions.cs
index 297d49816..b9a3d1d24 100644
--- a/src/ImageSharp/Memory/Buffer2DExtensions.cs
+++ b/src/ImageSharp/Memory/Buffer2DExtensions.cs
@@ -38,9 +38,6 @@ namespace SixLabors.ImageSharp.Memory
         /// <exception cref="InvalidOperationException">
         /// Thrown when the backing group is discontiguous.
         /// </exception>
-        // TODO: Review all usages, should be only used with buffers which do not scale fully with image size!
-        // Remove [Obsolete], when done!
-        [Obsolete("TODO: Review all usages!")]
         internal static Span<T> GetSingleSpan<T>(this Buffer2D<T> buffer)
             where T : struct
         {
@@ -64,9 +61,6 @@ namespace SixLabors.ImageSharp.Memory
         /// <exception cref="InvalidOperationException">
         /// Thrown when the backing group is discontiguous.
         /// </exception>
-        // TODO: Review all usages, should be only used with buffers which do not scale fully with image size!
-        // Remove [Obsolete], when done!
-        [Obsolete("TODO: Review all usages!")]
         internal static Memory<T> GetSingleMemory<T>(this Buffer2D<T> buffer)
             where T : struct
         {
diff --git a/tests/ImageSharp.Tests/ImageSharp.Tests.csproj b/tests/ImageSharp.Tests/ImageSharp.Tests.csproj
index fdefa38e7..34cdca49a 100644
--- a/tests/ImageSharp.Tests/ImageSharp.Tests.csproj
+++ b/tests/ImageSharp.Tests/ImageSharp.Tests.csproj
@@ -2,8 +2,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-<!--    <TargetFrameworks>netcoreapp3.1;netcoreapp2.1;net472</TargetFrameworks>-->
-    <TargetFrameworks>netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;netcoreapp2.1;net472</TargetFrameworks>
     <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
     <DebugSymbols>True</DebugSymbols>
     <AssemblyName>SixLabors.ImageSharp.Tests</AssemblyName>