The 30-day maintenance plan mentioned in the email is for version 8, which those of us on maintenance for version 7/7.5 get as part of that maintenance plan (which if for our 7 licenses). So if you want to get 8.5 as part of your maintenance plan - it will probably be cheaper to pay for maintenance and get 8.5 "free" as part of the maintenance agreement on your 8 license, than it will be to just buy an upgrade to 8.5 from 8. At least that's how understand it