This is all open source stuff but it does give an insight
"the
APG-83 active electronically scanned array radar, above-wing fuel tanks for increased range, and an automatic ground collision avoidance system. The Block 70 also has a structural service life of 12,000 hours, compared to 4,000 to 8,000 hours for earlier versions of the F-16",
And
Lockheed's promotional video shows the fighter with a remarkable ten missiles—eight medium range, radar-guided AMRAAM missiles plus two AIM-9X Sidewinder missiles. The F-21 can be seen carrying a Sniper electro-optical targeting pod, also produced by Lockheed Martin. In service with the U.S. Air Force, the Sniper pod provides HD forward-looking infrared (also known as thermal imaging), a dual mode laser, video data link, and digital data recorder. The F-21 also features an aerial refueling probe for refueling using the drogue system and a huge flat panel cockpit display.
This hints at structural improvement durability and strength.