ECC6 Upgrade and EHP 4 because of a CRM7 in the landscape?

Hi,

I am in the way to upgrade my SAP 4.6c system to ECC6.

In my overall landscape, I have a CRM 7 installed.

Do you believe I need to perform a simple ECC6 upgrade or a ECC6 upgrade including EHP4 SR1?

In other words, is it mandatory to go through the Upgrade + EhP4 because I have a CRM 7 around?

Thank you,

Chris