They renegotiated the leases on the 49 B+ saabs and got rid of the rest of the ones they didn't want. From what I understand the leases aren't tied to YEARS but are tied to block hours. Obviously the new DL network as they continue to combine the airlines doesn't require 49 saabs. Will there be a replacement? I hope so. The writing was on the wall for them to all leave at some point. It's just a surprise to see them start to go so soon. We'll see what happens... it's not September yet according to my calendar.
And as for knowing what's going on... nobody knows. Everyone seems to have their own version of speculation which is based and fueled by other speculation. This is further fueled by the companies inability or lack of desire to tell us what's going on. IMO... they don't really know what's going to happen either.