Dynamics Ax 2009 compatibilitywith .Net 4

I was recently developing a class library application for Dynamics Ax 2009  on Visual studio 2010. When I tried adding it  to the reference node, Ax threw an error informing that it is not a valid .Net assembly.  I had to change the version to 3.5 in the build properties of the VS Project to generate a compatible dll. I’m not sure if .Net 4 is compatible with Ax2009 but made it a note here….

Here is some compatibility information from SE Team  SE Team – Compatibility testing results but it only says Ax2009 and .Net 4 can run side by side. So guys it is good to check your .Net versions and try before you absorb it in to ax when facing a similar error.

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