Is there a concrete number of bug fixes that were incorporated in 4.50 that did not make it into version 4.40? When PU4 came out, PU10 did as well and sometimes Sage fixes things in 4.40 and in 4.50, and sometimes just in 4.50 and not going backwards. I'm wondering if that number would make for an incentive for someone to upgrade (although not all issues affect everyone).