Hey Everyone.. first time poster here so take it easy on me

I recently purchased a 2011 F250 6.7L to haul my 27 foot camper and its been doing great. But recently the check engine light has been on. One of my neighbors gave me a Edge Products CTS module that hooks up to my OBD2 port to check the codes and I got two codes:

P0471 - Exhaust Back pressure sensor circuit malfunction
P20EE - Catalyst Efficiency Below Threshold Bank 1

I recently have taken it to Ford and they have replaced one of my Exhaust Temperature Sensors, just as an FYI if the info helps.

I'm new to the diesel world and am just starting to learn the motor. Any help will be greatly appreciated!!