Are the Redhat Python Packages compatible with Install Packages from Python?

I'm on a project where an outside company wants to transfer data from our systems to their systems. I want to make sure we won't have any comparability issues when it comes time to transfer data.

The outside company is going to use Python as the language to make this happen and we are using Python too on our end. I'm teaching myself Python in my freetime and I know that older versions of Python aren't compatible with newer versions (for example 2.6/2.7 isn't compatible with 3.2/3.3).

The version of Python that we have installed on RHEL6 x86_86 is 2.6.6-64.el6.

I see on Python's website, you can still download v2.6.6 however they recommend to download and install v2.7 instead.

My question is that will the outside company have to use a version of Python that will work with what is currently installed on RHEL6, for example the same version or something in the 2.7 range? Or will they have to use the same version of Python that we are using?

thanks