Adobe has announced an important change in upgrade qualifications for Creative Suite 6 products: to qualify for CS6 (not yet released) with an upgrade discount, customer will have to own the previous version licence (CS5 or CS5.5).
This would be probably the new upgrade pricing model from now on, or an attempt to force customers to keep updating alive constantly, while so far many ones skipped releases since CS products are not cheap...
Until end of 2011 a discount will be offered to customer of version prior to CS5 in order to qualify for upcoming CS6 as upgrades (and not full price).