Apparently, because the original Star Wars had to run on such a low budget, the original control yolks, the devices that steer the ship, weren’t built with any springs that stayed in place.
While digital effects have become a major way for films to create that which isn’t real, Star Wars: The Force Awakens still decided to do a lot of their effects practically.
As Abrams tells the story, Harrison Ford noticed the change immediately upon sitting at the controls again.
This meant that when it came time to recreate the iconic Millennium Falcon, the set was rebuilt to resemble the original one in every possible detail.