[wix-users] Getting related bundle state during update

[Pavol Kovalik]

I'm building a custom managed bootstrapper in WPF. During an upgrade, I
need to retrieve some persisted variables from the related (previous)
bundle. Is there any BootsrapperCore API I could use that I missed?

Otherwise I'm considering to do following:
Get directory path from
[HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{RELATED-BUNDLE-GUID}]\BundleCachePath
Look for "state.rsm" file
Manually parse it using BinaryReader

Am I on the right track here?