F-16s role in current USAF…

I’ve been reading random articles lately of AFM, Combat Aircraft etc and I keep coming across articles saying F-16s from various Air National Guard units and so forth are JUST NOW being upgraded to F-16C Block 40/42 and in some cases even to a block 25?? Can this be true? My question to anyone who cares is, what is the official status of the F-16 in the USAF? I find conflicting articles, and I am confused. I know the USAF does NOT operate F-16E/F block 60s, those were for export, but do they operate block 50/52s and if so, what is the role? Don’t F-22s, F-15Cs & F-15E strike eagles take care of 99% of the USAFs missions?