Xamarin iOS SDK 15.6.0.3 break

iOSSDK.Compat.targets

<Project>
    <!--
        iOS SDK Compatibility
        iOS SDK 15.6.0.3 introduces a breaking change to the output of _DetectAppManifest
        The output has been renamed to reflect a change from a "private" to "public" MSBuild parameter
    -->
    <Target Name="FixSwiftTarget"
            AfterTargets="_DetectAppManifest"
            BeforeTargets="_SwiftFrameworksMac">
      <PropertyGroup Condition="$(_AppManifest) == '' AND $(AppBundleManifest) != ''">
        <_AppManifest>$(AppBundleManifest)</_AppManifest>
      </PropertyGroup>

      <PropertyGroup Condition="$(MtouchSdkVersion) == ''">
         <_SdkVersion Condition="'$(_SdkVersion)' == ''">0.0</_SdkVersion>
        <MtouchSdkVersion>$(_SdkVersion)</MtouchSdkVersion>
      </PropertyGroup>
    </Target>
</Project>

YourProject.iOS.csproj

<?xml version="1.0" encoding="utf-8"?>
<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Import Project="iOSSDK.Compat.targets" />
  <!-- The rest of the file left out for brevity -->
</Project>