2013 Ram questions

I bought a new 2013 Ram last month and took it in today for it's first service. I had noticed some shuttering with the trans/converter and mentioned it to them. They told me there was an update on driveability issues and installed it. Does anyone know what it the update entails?

Also, Any suggestions on bumping fuel milage a bit more? I installed a tonneau cover and put a K&N air filter in, replacing the stock filter. raised the tire pressure up and use the cruise control. Highway milage is about 18-19. hoping to be in 20's
Thanks!