After the previous post
about .NET 2.0 and compatibility with the past, I've received an interesting
feedback by SeeR that signalled me a strange behaviour and an undocumented case
of incompatibility.
This "bad case" is this: create a .DLL
with a UserControl in VS 2003 and embed it in an HTML page using <object> tag (to use it in your
browser), write some code thar requires special rights and publish it on
server. Now on the client computer make sure you have .NET 1.1 and .NET 2.0
installed. Grant required rights in .NET 1.1 configuration MMC snap-in. Try to
run those page.
Result? A Security exception logged in
IEHostLogFile and information that it is throwed by library with version 2.0.0.0
. User see only empty page with default picture instead of UserControl.
Your UserControl should work with .NET 1.1 but insted it doesn't work. 
The response from Microsoft is that this behaviour
is by design: controls in the browser automatically upgrade to the
latest version of the framework installed. Applications do not. They
have no plans to change this at this stage due to the complexity around the fact
that currently you cannot load multiple copies of the .NET Framework in the same
memory space.
So, remember this exception on the standard .NET 2.0 behaviour when you
deploy your projects...