Enfield location closed on September 13. Sign was up on the door alerting patrons according to a photo from this source
https://patch.com/connecticut/enfield/dennys-closes-enfield-location-after-more-45-years-business
West Haven location closed on September 6.
https://patch.com/connecticut/westhaven/denny-s-closes-abruptly-west-haven
This leaves 6 locations intact in CT including Vernon.
There is one in Scott Township, PA that now closes at 5PM. Kind of shocking as Dennys was always known as the 24-hour place (nothing good ever happens there at bar closing time).
I have a nephew who used to work there who says that they are really struggling to hire help and hence had to reduce their hours of operation. He is also hearing from his ex-coworkers that the restaurant may close.