Windowsill holder for dog door and beam Mk2

Last year I designed and printed this little bracket to mount on a windowsill. The dog door sits in it, conveniently out of the way and unlikely to fall over, when not in use; also, a contraption of two-by-fours I use to keep the dog door in place (the cat has figured out how to pull it off otherwise) has its own spot for stashing.

After most of a year's use, the bracket shows a tendency to weaken and eventually snap near the bottom in front. This remix strengthens at front and back, where th