SOMETHING has to change to comply with emissions regulations.. and most would assume fuel economy and/or power would suffer or it would've been right in the first place during the initial testing/development.
Could be the sending unit, or the entire tank. Perhaps just keep filling the tank on a routine/schedule so you don't run out. Especially if you're out of warranty as that entire replacement would be costly.
Welcome! Just have a read around the forums and educate yourself.. plenty of good, plenty of bad. Be sure to share some pictures or start a "garage" for your truck here: https://www.ecodieselram.com/forum/garage/
Welcome, you know what they say about opinions... :D
I would suggest reading around the forums here as we've got plenty of topics covering that same subject.
We've got a ton of threads around this. Seems to be no permanent solution that I've come across.. many people find different things will fix the issue, and others still get the message from time to time...