Hi Tim,

Thanks for the reply. Your comments are exactly what I am trying to determine. I.e. is the dll's specific compile framework required, or are runtime frameworks backward compatible?

The reason I am asking is we have a client ( remote so we can't determine machine config ourselves ) that seems to have placed a .Net 2.0 exe on a machine that (supposedly) only has the .Net 4.0 Framework on it and the application seems to run. We are trying to get further details of the exact machine config.

Bill

>>We haven't run into this issue before and are trying to get some quick answers w/o doing research.
>>
>>1) Will a .Net application developed/compiled under an earlier .Net framework ( e.g. 2.0 ) run under a later framework ( e.g. 4.0 )? I.e. will an application compiled under .Net 2.0 is placed on a machine having only .Net 4.0 run properly ( or at all )?
>>
>>2) If a machine has more than one .Net Version Framework installed on it, will each appliction/dll on the machine run under it's compiled framework, or will the OS run all applications/dlls under the latest framework on the machine?
>>
>>Thanks,
>>Bill
>
>Many of the dll's are different from version 2.0 to 4.0. If the application is using the dll's from dot net 2.0/ 3.0/3.5 you will need to have that framework installed as well.
>Tim