Poland has started negotiations with Ukraine for the transfer of Soviet-era MiG-29 warplanes, formerly owned by East Germany, subsequently integrated by reunited Germany, and used for a while by the Luftwaffe, which upgraded them to NATO standards, and finally given to the Siły Powietrzne.

The transfer of the fourteen remaining MiG-29 is subject to reaching the lifespan; the aircrafts will not be further upgraded by Poland.
The tasks currently performed by the MiG-29 will be assumed by the upgraded F-16 Jastrzab to Viper or Block 70/72 standard and by the lightweight fighter-bomber KAI FA-50, of which Poland has in progress the acquisition of 48 units, pending any decisions from the Warsaw Government on the purchase of a line of air superiority fighters to flank the F-35A Husarz.
The transfer to Ukraine is intended as military aid within the policy of the Alliance in support of Ukraine and as a measure to maintain the security of the eastern flank of NATO.
Technological Partnership between Ukraine and Poland
The ongoing negotiation with Ukraine anticipates some form of compensation from Kiev for the sharing of advanced technologies developed by Ukrainian industries for drones and missiles, in order to jointly acquire and develop new skills and capabilities in the defense and industrial sectors by Poland.
For Poland, the MiG-29s have largely a residual value and their transfer does not change the situation much, while for Ukraine, these fighter planes can still be useful, filling the heavy losses so far suffered in almost four years of war with Russia.
Source and photo credit @Polish Armed Forces General Staff