diff --git a/src/Postal.Mvc3/Postal.Mvc3.csproj b/src/Postal.Mvc3/Postal.Mvc3.csproj
index 3f085e5..14bd7b7 100644
--- a/src/Postal.Mvc3/Postal.Mvc3.csproj
+++ b/src/Postal.Mvc3/Postal.Mvc3.csproj
@@ -39,6 +39,15 @@
     <AssemblyOriginatorKeyFile>..\Postal.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="Microsoft.Threading.Tasks">
+      <HintPath>..\..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.Threading.Tasks.Extensions">
+      <HintPath>..\..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.Extensions.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.Threading.Tasks.Extensions.Desktop">
+      <HintPath>..\..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.Extensions.Desktop.dll</HintPath>
+    </Reference>
     <Reference Include="Microsoft.Web.Infrastructure, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
       <Private>True</Private>
       <HintPath>..\packages\Microsoft.Web.Infrastructure.1.0.0.0\lib\net40\Microsoft.Web.Infrastructure.dll</HintPath>
@@ -48,6 +57,16 @@
     </Reference>
     <Reference Include="System" />
     <Reference Include="System.Core" />
+    <Reference Include="System.IO">
+      <HintPath>..\..\packages\Microsoft.Bcl.1.1.8\lib\net40\System.IO.dll</HintPath>
+    </Reference>
+    <Reference Include="System.Net" />
+    <Reference Include="System.Runtime">
+      <HintPath>..\..\packages\Microsoft.Bcl.1.1.8\lib\net40\System.Runtime.dll</HintPath>
+    </Reference>
+    <Reference Include="System.Threading.Tasks">
+      <HintPath>..\..\packages\Microsoft.Bcl.1.1.8\lib\net40\System.Threading.Tasks.dll</HintPath>
+    </Reference>
     <Reference Include="System.Web" />
     <Reference Include="System.Web.Helpers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
       <Private>True</Private>
@@ -126,6 +145,7 @@
     </Compile>
   </ItemGroup>
   <ItemGroup>
+    <None Include="app.config" />
     <None Include="packages.config" />
   </ItemGroup>
   <ItemGroup>
@@ -139,6 +159,11 @@
     </PropertyGroup>
     <Error Condition="!Exists('$(SolutionDir)\.nuget\NuGet.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(SolutionDir)\.nuget\NuGet.targets'))" />
   </Target>
+  <Import Project="..\..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets" Condition="Exists('..\..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets')" />
+  <Target Name="EnsureBclBuildImported" BeforeTargets="BeforeBuild" Condition="'$(BclBuildImported)' == ''">
+    <Error Condition="!Exists('..\..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets')" Text="This project references NuGet package(s) that are missing on this computer. Enable NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=317567." HelpKeyword="BCLBUILD2001" />
+    <Error Condition="Exists('..\..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets')" Text="The build restored NuGet packages. Build the project again to include these packages in the build. For more information, see http://go.microsoft.com/fwlink/?LinkID=317568." HelpKeyword="BCLBUILD2002" />
+  </Target>
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
   <Target Name="BeforeBuild">
diff --git a/src/Postal.Mvc3/app.config b/src/Postal.Mvc3/app.config
new file mode 100644
index 0000000..3c73782
--- /dev/null
+++ b/src/Postal.Mvc3/app.config
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <runtime>
+    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
+      <dependentAssembly>
+        <assemblyIdentity name="System.Runtime" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-2.6.8.0" newVersion="2.6.8.0" />
+      </dependentAssembly>
+      <dependentAssembly>
+        <assemblyIdentity name="System.Threading.Tasks" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-2.6.8.0" newVersion="2.6.8.0" />
+      </dependentAssembly>
+    </assemblyBinding>
+  </runtime>
+</configuration>
\ No newline at end of file
diff --git a/src/Postal.Mvc3/packages.config b/src/Postal.Mvc3/packages.config
index 7412d63..c3a8d2b 100644
--- a/src/Postal.Mvc3/packages.config
+++ b/src/Postal.Mvc3/packages.config
@@ -3,6 +3,9 @@
   <package id="Microsoft.AspNet.Mvc" version="3.0.20105.1" targetFramework="net40" />
   <package id="Microsoft.AspNet.Razor" version="1.0.20105.408" targetFramework="net40" />
   <package id="Microsoft.AspNet.WebPages" version="1.0.20105.408" targetFramework="net40" />
+  <package id="Microsoft.Bcl" version="1.1.8" targetFramework="net40" />
+  <package id="Microsoft.Bcl.Async" version="1.0.168" targetFramework="net40" />
+  <package id="Microsoft.Bcl.Build" version="1.0.14" targetFramework="net40" />
   <package id="Microsoft.Web.Infrastructure" version="1.0.0.0" targetFramework="net40" />
   <package id="RazorEngine" version="2.1" targetFramework="net40" />
 </packages>
\ No newline at end of file
diff --git a/src/Postal.Mvc4/Postal.Mvc4.csproj b/src/Postal.Mvc4/Postal.Mvc4.csproj
index 994c54d..c99bac1 100644
--- a/src/Postal.Mvc4/Postal.Mvc4.csproj
+++ b/src/Postal.Mvc4/Postal.Mvc4.csproj
@@ -39,6 +39,15 @@
     <AssemblyOriginatorKeyFile>..\Postal.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="Microsoft.Threading.Tasks">
+      <HintPath>..\..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.Threading.Tasks.Extensions">
+      <HintPath>..\..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.Extensions.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.Threading.Tasks.Extensions.Desktop">
+      <HintPath>..\..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.Extensions.Desktop.dll</HintPath>
+    </Reference>
     <Reference Include="Microsoft.Web.Infrastructure, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
       <Private>True</Private>
       <HintPath>..\..\packages\Microsoft.Web.Infrastructure.1.0.0.0\lib\net40\Microsoft.Web.Infrastructure.dll</HintPath>
@@ -50,6 +59,16 @@
     <Reference Include="System" />
     <Reference Include="System.Core" />
     <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.IO">
+      <HintPath>..\..\packages\Microsoft.Bcl.1.1.8\lib\net40\System.IO.dll</HintPath>
+    </Reference>
+    <Reference Include="System.Net" />
+    <Reference Include="System.Runtime">
+      <HintPath>..\..\packages\Microsoft.Bcl.1.1.8\lib\net40\System.Runtime.dll</HintPath>
+    </Reference>
+    <Reference Include="System.Threading.Tasks">
+      <HintPath>..\..\packages\Microsoft.Bcl.1.1.8\lib\net40\System.Threading.Tasks.dll</HintPath>
+    </Reference>
     <Reference Include="System.Web" />
     <Reference Include="System.Web.Helpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
       <Private>True</Private>
@@ -123,6 +142,7 @@
     </Compile>
   </ItemGroup>
   <ItemGroup>
+    <None Include="app.config" />
     <None Include="packages.config" />
   </ItemGroup>
   <ItemGroup>
@@ -136,6 +156,11 @@
     </PropertyGroup>
     <Error Condition="!Exists('$(SolutionDir)\.nuget\NuGet.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(SolutionDir)\.nuget\NuGet.targets'))" />
   </Target>
+  <Import Project="..\..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets" Condition="Exists('..\..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets')" />
+  <Target Name="EnsureBclBuildImported" BeforeTargets="BeforeBuild" Condition="'$(BclBuildImported)' == ''">
+    <Error Condition="!Exists('..\..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets')" Text="This project references NuGet package(s) that are missing on this computer. Enable NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=317567." HelpKeyword="BCLBUILD2001" />
+    <Error Condition="Exists('..\..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets')" Text="The build restored NuGet packages. Build the project again to include these packages in the build. For more information, see http://go.microsoft.com/fwlink/?LinkID=317568." HelpKeyword="BCLBUILD2002" />
+  </Target>
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
   <Target Name="BeforeBuild">
diff --git a/src/Postal.Mvc4/app.config b/src/Postal.Mvc4/app.config
new file mode 100644
index 0000000..3c73782
--- /dev/null
+++ b/src/Postal.Mvc4/app.config
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <runtime>
+    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
+      <dependentAssembly>
+        <assemblyIdentity name="System.Runtime" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-2.6.8.0" newVersion="2.6.8.0" />
+      </dependentAssembly>
+      <dependentAssembly>
+        <assemblyIdentity name="System.Threading.Tasks" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-2.6.8.0" newVersion="2.6.8.0" />
+      </dependentAssembly>
+    </assemblyBinding>
+  </runtime>
+</configuration>
\ No newline at end of file
diff --git a/src/Postal.Mvc4/packages.config b/src/Postal.Mvc4/packages.config
index 5d50028..60e8ed2 100644
--- a/src/Postal.Mvc4/packages.config
+++ b/src/Postal.Mvc4/packages.config
@@ -3,6 +3,9 @@
   <package id="Microsoft.AspNet.Mvc" version="4.0.30506.0" targetFramework="net40" />
   <package id="Microsoft.AspNet.Razor" version="2.0.30506.0" targetFramework="net40" />
   <package id="Microsoft.AspNet.WebPages" version="2.0.30506.0" targetFramework="net40" />
+  <package id="Microsoft.Bcl" version="1.1.8" targetFramework="net40" />
+  <package id="Microsoft.Bcl.Async" version="1.0.168" targetFramework="net40" />
+  <package id="Microsoft.Bcl.Build" version="1.0.14" targetFramework="net40" />
   <package id="Microsoft.Web.Infrastructure" version="1.0.0.0" targetFramework="net40" />
   <package id="RazorEngine" version="3.3.0" targetFramework="net40" />
 </packages>
\ No newline at end of file
diff --git a/src/Postal.Mvc5/Postal.Mvc5.csproj b/src/Postal.Mvc5/Postal.Mvc5.csproj
index c7e042e..980784c 100644
--- a/src/Postal.Mvc5/Postal.Mvc5.csproj
+++ b/src/Postal.Mvc5/Postal.Mvc5.csproj
@@ -19,7 +19,7 @@
     <DebugType>full</DebugType>
     <Optimize>false</Optimize>
     <OutputPath>bin\Debug\</OutputPath>
-    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <DefineConstants>TRACE;DEBUG;NET45</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
diff --git a/src/Postal/EmailService.cs b/src/Postal/EmailService.cs
index d829a77..d413059 100644
--- a/src/Postal/EmailService.cs
+++ b/src/Postal/EmailService.cs
@@ -59,51 +59,20 @@ public void Send(Email email)
         /// </summary>
         /// <param name="email">The email to send.</param>
         /// <returns>A <see cref="Task"/> that completes once the email has been sent.</returns>
-        public Task SendAsync(Email email)
+        public async Task SendAsync(Email email)
         {
             // Wrap the SmtpClient's awkward async API in the much nicer Task pattern.
-            // However, we must be careful to dispose of the resources we create correctly.
-            var mailMessage = CreateMailMessage(email);
-            try
-            {
-                var smtp = createSmtpClient();
-                try
-                {
-                    var taskCompletionSource = new TaskCompletionSource<object>();
-
-                    smtp.SendCompleted += (o, e) =>
-                    {
-                        smtp.Dispose();
-                        mailMessage.Dispose();
-
-                        if (e.Error != null)
-                        {
-                            taskCompletionSource.TrySetException(e.Error);
-                        }
-                        else if (e.Cancelled)
-                        {
-                            taskCompletionSource.TrySetCanceled();
-                        }
-                        else // Success
-                        {
-                            taskCompletionSource.TrySetResult(null);
-                        }
-                    };
-
-                    smtp.SendAsync(mailMessage, null);
-                    return taskCompletionSource.Task;
-                }
-                catch
+            using (var mailMessage = CreateMailMessage(email))
+            { 
+                using (var smtp = createSmtpClient())
                 {
-                    smtp.Dispose();
-                    throw;
+#if NET45
+                    await smtp.SendMailAsync(mailMessage);
+#else
+                    await smtp.SendTaskAsync(mailMessage);
+#endif
                 }
             }
-            catch
-            {
-                mailMessage.Dispose();
-                throw;
-            }
         }
 
         /// <summary>