Well -- we have a beta program for it. You can email
beta-zcs@zimbra.com with your primary contact name, email, company name and product (version + platform). Then we can add you to the Beta list.
This is really designed for ZCS/ZCO 7.0, since 7.0 is the version this works under, and we generally don't support ZCO running against earlier servers, but it should work for the most part with 6.0.8. There are some new features that probably won't work. Of course, we're not testing against 6.0.8 at all.
So I recommend moving to 7.0. But we can still put you on the beta.