Multi-path on DEVPATH v2.0 QFE is available
See
https://support.microsoft.com/default.aspx?scid=kb;en-us;915430&sd=rss&spid=8291
for more detail.
The other problem reported by Isaac
https://blogs.msdn.com/junfeng/archive/2005/12/13/503059.aspx#546000
[b]
If you add the section
<runtime>
<developmentMode developerInstallation="true"/>
</runtime>
to machine.config but you don't define any DEVPATH environment variable, your EXE will crash.
is not fixed by this QFE. It is a different problem and may be fixed by a separate QFE.