How do I detect the currently installed features during a MajorUpgrade using WiX Burn MBA Bundles?

I'm using WiX 3.7's Burn/Managed Bootstrapper Application features to create a custom MBA-based installer. For each of the packages in my bundle's chain, when performing a MinorUpdate, I can easily detect which of the package features are already installed to ensure I maintain those feature selections during the upgrade by using these events provided in the WiX base class for the bootstrapper: `DetectPackageComplete`, `DetectMsiFeature`, `DetectRelatedBundle`, `DetectRelatedMsiPackage`, `DetectComplete`. However, during a MajorUpgrade, I'm only seeing a way to determine which package(s) are installed, but am not seeing how to determine which features are installed, as the DetectMsiFeature event does not fire. I tried using the `MigrateFeatures` flag on the product's configuration, but that doesn't seem to work (or I'm not using it right). What is the correct way to detect/migrate existing features when performing a MajorUpgrade using a Custom Managed Bootstrapper Application in WiX? Some file snippets: Note: I can provide a fully working VS Solution with all code if that is helpful. Bundle.wxs: ``` <Wix xmlns="http://schemas.microsoft.com/wix/2006/wi" xmlns:bal="http://schemas.microsoft.com/wix/BalExtension"> <Bundle Name="Bootstrapper1" Version="1.1.0.0" Manufacturer="Knights Who Say Ni" UpgradeCode="e6fbf160-d1d9-4b38-b293-94d60eae876f" Compressed="yes"> <BootstrapperApplicationRef Id="ManagedBootstrapperApplicationHost" > <Payload SourceFile="$(var.ManagedBootstrapperApplication.TargetPath)" /> <!-- other files here --> </BootstrapperApplicationRef> <Chain> <PackageGroupRef Id="NetFx40Web" /> <MsiPackage SourceFile="$(var.SetupProject1.TargetPath)" EnableFeatureSelection="yes" Vital="yes" Compressed="yes" /> </Chain> </Bundle> </Wix> ``` Product.wxs: ``` <Wix xmlns="http://schemas.microsoft.com/wix/2006/wi"> <Product Id="*" Name="SetupProject1" Language="1033" Codepage="1252" Version="1.1.0.0" Manufacturer="Knights Who Say Ni" UpgradeCode="5fcd463a-3287-4fdf-bf00-d5d74baeccda"> <Package InstallerVersion="200" Compressed="yes" InstallScope="perMachine" /> <MajorUpgrade AllowSameVersionUpgrades="no" AllowDowngrades="no" MigrateFeatures="yes" DowngradeErrorMessage="Bring me a shrubbery!" /> <MediaTemplate EmbedCab="yes" /> <Feature Id="feature_one" Title="Primary Feature" Level="1"> <Component Id="CMP_emptyFile1" Guid="{1740AFA6-A98F-482A-B319-A153AA1BEF10}" Directory="INSTALLFOLDER"> <File Id="file_emptyFile1" Checksum="yes" KeyPath="yes" Source="TextFile1.txt" /> </Component> </Feature> <Feature Id="feature_Two" Title="Optional Feature" Level="2"> <Component Id="CMP_emptyFile2" Guid="{F0831C98-AF35-4F5E-BE9A-2F5E3ECF893C}" Directory="INSTALLFOLDER"> <File Id="file_emptyFile2" Checksum="yes" KeyPath="yes" Source="TextFile2.txt" /> </Component> </Feature> </Product> </Wix> ``` CustomBootstrapper.cs ``` public class CustomBootstrapperApplication : BootstrapperApplication { protected override void Run() { DetectPackageComplete += HandlePackageDetected; DetectMsiFeature += HandleFeatureDetected; DetectRelatedBundle += HandleExistingBundleDetected; DetectRelatedMsiPackage += HandleExistingPackageDetected; DetectComplete += HandleDetectComplete; this.Engine.Detect(); //blocks here until DetectComplete fires... } private void HandleExistingPackageDetected(object sender, DetectRelatedMsiPackageEventArgs e) { Log(string.Format("Detected Related Package {2} ({1}) at version {3} which is a {0}", e.Operation, e.PackageId, e.ProductCode, e.Version)); } private void HandleExistingBundleDetected(object sender, DetectRelatedBundleEventArgs e) { Log(string.Format("Detected Related {2} Bundle {0} at version {1} which is a {3}", e.ProductCode, e.Version, e.RelationType, e.Operation)); } private void HandleFeatureDetected(object sender, DetectMsiFeatureEventArgs e) { Log(string.Format("Feature {0} from Package {1} detected in state {2}", e.FeatureId, e.PackageId, e.State)); } private void HandlePackageDetected(object sender, DetectPackageCompleteEventArgs e) { Log(string.Format("Package {0} Detected in State {1}", e.PackageId, e.State)); } private void HandleDetectComplete(object sender, DetectCompleteEventArgs e) { /* release the main thread to continue with work */ } } ``` Output on upgrade: Note that the package and two features were both installed at v1.0.0 and detected in state Absent. The Related Package was detected, but no feature details are included. ``` Detected Related Upgrade Bundle {5eff0a3c-4b0d-4fd9-875f-05117c07f373) at version 1.0.0.0 which is a MajorUpgrade Package NetFx4OWeb Detected in State Present Detected Related Package {540AE32D-75C0-4BF3-A72D-ADBE97FSFF3E} (SetupProject1.msi) at version 1.0.0.0 which is a MajorUpgrade Feature feature_one from Package SetupProjectl.msi detected in state Absent Feature feature_Two from Package SetupProjecti .msi detected in state Absent Package SetupProject1.msi Detected in State Absent ```