No apparent equipment change. Just minor time table tweaks as far as I can see in the itin. It's - again - extremely frustrating, what I try to do is logging in twice a day and secure my seats
Have you tried calling SMS and asking if you still have the seats assigned. This has happened to me a number of times and SMS just needed to reload it so I could see it on the DL website. They said I hadn't lost the seat assignment. The website showed unassigned.