He uses the Mk 50 in Infinity War, and last we saw him in Spiderman: Homecoming he was wearing 47, 46 in Civil War and 45 in Age of Ultron. Up until now we’ve been able to keep track of every suit he has used in the MCU starting with the Mk 1 in the first Iron Man film, even if a whole bunch of them were blink and you miss it sightings from the “house party protocol” in Iron Man 3.
Good question. The Marvel wiki just notes that they existed but is silent on any details.
Maybe the problem with them was that the nanites had to be stored in Tony’s ass.
I happened to watch Spider-man last night. During “moving day” there’s an Iron Man armor in the background of plane. My headcanon is that’s Mark 48.
Apparently the Hulkbuster suit is not the same one as the one in Ultron, so that would be 48 or 49.