About half of these MIGS are upgraded to NATO standards. Meaning they have improved radar, can carry AIM air to air missiles, HARMs and ER-JDAM bombs.
I don't think that's the case but I could be wrong.
AFAIK the upgraded Polish MiG's received a new mission computer with a 1553 data bus (so in theory it could use NATO weapons), but every picture I've seen of them have R-73's under the wing, not AIM-9's.
They have a digital cockpit with western-standard avionics, and NATO IFF and Comms, but I don't believe they ever integrated any NATO weapons. They weren't really intended to be anything other than point-defense.
I don't see these as game-changers for Ukraine. They are stuck at low altitude, and the AAM's lose a lot of kinematic performance when launched from low altitudes. Ukraine needs to chase away the MiG-31's and bombers that are operating from outside Ukrainian airspace, and go after the Su-30's and Su-27's that are operating over the front lines.
For that they need a western fighter with a long-range, active radar guided AAM- preferably the MDBA Meteor, which uses a ramjet motor, and doesn't have so much of a low-altitude penalty as AMRAAM.
The Gripen is best suited for Ukraine. It can be operated from unimproved strips (including roads), dispersed locations with small crews (only one of whom needs specialized training), and it can handle all the western weapons.
F-16's need a lot of support people and pristine runways, which means a large fixed base that would be an easy target for Russia's long range missiles. A Gripen can be hidden in a barn...
