This article covers pretty much everyone but I'll quote the Panther stuff.
Carolina Panthers: A year-long study is under way in Charlotte to determine the upgrades needed at Bank of America Stadium, with the Panthers looking at a major renovation of the 16-year-old structure. There's no lease in Carolina, and owner Jerry Richardson has no succession plan for the club, so keeping the stadium updated is a priority for the team in keeping the region an attractive place to be.
What's fascinating about the above list is that of the seven clubs, only San Diego and Atlanta are thought to have a fighting chance at an entirely new stadium. It illustrates how the landscape has changed in a decade-and-a-half. It also underscores how even owners who opened stadiums in this millennia have some home improvement to do.
The focus for now is getting the Digital Antennae Systems (DAS) and Wifi up to speed and integrated, and that's a constantly moving target. The Cowboys, Colts, Patriots, Saints*, Panthers, Cardinals, Giants/Jets and Niners are among those leading the charge.
I love how people on the outside love to hint that the Panthers could leave with phrases like "no lease" and "no succession plan". I don't really see them ever meeting Roger Goodell's requirements to relocate.
What do you guy's think they could do to upgrade the BofA? I really don't see a way they could modify the bowl seating itself. Maybe add more stuff to the concourses and luxury boxes. Maybe bigger scoreboards. The one thing I do know is ticket and PSL prices will go up.