Apps created in XCode 4 in Xcode 2.5?

[scuba31]

I'll keep it short;
I need to security test an app made by an external company in XCode 4. My company only has access to Mac's running OS X 10.4 so I've found XCode 2.5 is the highest version of XCode I'll be able to install.

Will the files run ok that have been created in XCode 4 or will there be compatability issues?

Thanks.