This is my first cover from disputed territory called Donetsk People's Republic, and it's same like with Luhansk People's Republic. The Donetsk People's Republic is a declared people's republic and proto-state in the Donetsk Oblast of Ukraine recognized only by the partially recognized South Ossetia and Luhansk People's Republic. Ukraine is at war with the DPR and Luhansk People's Republic (LPR) and has designated it as a terrorist group. It was part of the unrecognized Novorossiya confederation with the LPR until 20 May 2015, and since February 2015, has postured itself as the successor to the historic Donetsk–Krivoy Rog Soviet Republic.
There's no international postal service in Donetsk, only domestic. So
you can receive mail only to address within Donetsk, as you can see on
this cover. This stamp on cover is from set Khomutovsky Steppe, issued on 5.6.2018.