Despite Ukraine being at war with Russia, and Turkey an ally of Russia in Syria, business is business when it comes to finding export customers for your weapons. Moreover, Russia and Turkey are more frenemies of convenience in Syria that true allies. After all, Turkey is a member of NATO, a cold war era organization created to deal with Russian aggression. Ukraine is seeking to join NATO and being on good terms with Black Sea NATO nations like Turkey, Romania and Bulgaria is important.
Turkey has its first export customer, Ukraine, for its new self-propelled Korkut 35mm autocannon air defense system. Ukraine has been a customer for several Turkish weapons systems. Before that Ukraine supplied Turkey with several items of military technology that Turkey had not developed yet and proved very useful.
Since the 1990s Turkey has sought to develop its own defense industries and produce weapons for its own use and for export. There is a lot of competition and Turkey has learned to be flexible and creative when seeking customers and collaborators. Ukraine is an example of that.
Turkey introduced the Kortut in 2016 and has been using it in Syria for nearly as long. Korkut a tracked armored vehicle armed with twin 35mm autocannon that can fire 1,100 rounds a minute. This comes out to 18 a second, and most of the time Korkut will fire short (1-3 second) bursts. A Korkut battery consists of three 35mm gun vehicles and a command/control radar vehicle. The radar has a range of 70 kilometers while the 35mm guns are effective up to four kilometers. The 35mm gunner has an optical (visual) sight aided by the radar vehicle which also coordinates the fire of all three Korkut vehicles. Turkey is building enough Korkut equipment for 40 batteries and most are supposed to be in service by 2022.