requestvalidationmode causes issue with build script

I added

requestvalidationmode=2.0

to m开发者_如何学Cy page header.

Everything works great. However when I try and build this on my build server it crashes with this message:

errorASPPARSE: Error parsing attribute 'requestvalidationmode': Type 'MYASPFORM' does not have a public property named 'requestvalidationmode'.

Any ideas on what could be causing this?

I think this attribute was introduced in framework 4.0, is your build server building your project with the correct framework?