Up until 2014 Ukraine saw a bright future in further developing pre-1991 Soviet era weapons designs and selling them to export customers. Orders were coming in for these weapons until early 2014 when Russia decided to invade and annex portions of the Ukraine that Russia regretted parting with in 1991. Crimea was lost in a month then the Russians went after eastern Ukraine (Donbas) and that effort stalled, and is still stalled. Ukraine was surprised to discover that it was not lots of weapons, especially the one Ukraine had been building since 1991 that made the difference. It was eventually discovered that the Donbas effort was halted because many Ukrainians who were not in the military stepped forward and went to Donbas to fight using whatever they could scrounge up.
In any event Ukraine found its Russian suppliers (or components for weapons and much else) no longer available. Russia suffered the same fate but was better able to adapt. Many export projects were disrupted and when the Ukrainian military went looking for new weapons the first stop was Ukrainian firms making these updated Russian designs. Defending Ukraine took priority and that disrupted delivery schedules. A prime example of that is the T-84, a $4 million high-tech tank that was, on paper, equal to the American M1, the German Leopard 2, the Israeli Merkava and the Russian T-90.
The problem was the Ukrainian military found The T-84 it was more than they needed. Although the Ukrainian Army only ordered ten of them it was quickly discovered that cheaper tanks were more effective against the Russians (actually Russian backed Ukrainian rebels who were ethnic Russians who had long lived in the area) in Donbas. Where the T-84 really got into trouble was its main export customer; Thailand, who had ordered 49 of them in 2012. The first five T-84s were delivered to Thailand in early 2014 and after that deliveries slowed down rather than accelerated. The second five didn’t arrive until early 2015, at which point Ukrainian weapons manufacturers were all dedicated to supply Ukrainian troops in Donbas. Nevertheless ten more T-84s arrived in Thailand in early 2016 with another five arriving in late 2016. In the meantime Thailand was having second thought about the T-84 and ordered 28 Chinese VT4/MBT3000 tanks that were similar in performance and price to the T-84s and could be delivered more quickly and on schedule. Thailand has not cancelled the rest of the T-84 order but that is a possibility. China has become a major player in the post-1991 Russian weapons market, producing its own enhancements of Cold War era Russian designs but adding better tech and reliability. Ukraine can’t really compete, especially not with the Russian invasion still an issue because which the Russian advanced has been halted, the Russians are still occupying about half of Donbas. It was at that point that analysis of how Ukraine had stopped the Russians depended little (or not at all) on having the most modern weapons. This came as a blow to Ukrainian arms manufacturers, who depend on export sales. They again you can’t manufacture determination, resourcefulness and fighting spirit in a factory.
Nevertheless Ukraine has done some impressive weapons development. The T-84 is a Ukrainian modification of the Russian T-80, a failed Russian design that Ukrainian engineers managed to salvage. The Ukrainian version, the T-84 Oplot-M, was offered for sale in 2009. It was a 46 ton vehicle with a "western" style turret (as opposed to a Russian style one). The T-84 relies on multiple layers of armor protection (conventional steel, composites and reactive armor) and a Zaslon APS (active protective system) to deal with guided missiles and RPGs as well as modern electronics system to jam missile and other guidance systems and sensors. The fire control system is world-class and allows the T-84 to fight at night and in bad weather. The 125mm main gun uses a reliable auto-loader with 46 rounds of ammo on board and 28 (of up to four different types) are available for autoloading. The 125mm gun can also fire a laser guided missile against air or ground targets up to five kilometers away. The fire control system sensors can spot ground and air targets up to eight kilometers away. There is a 12.7mm machine-gun on top of the turret and a 7.62mm one coaxial with the main gun. The three man crew (commander, gunner, driver) use a lot of automation and electronics to operate a vehicle that has a top speed of 75 kilometers an hour on roads (and 45 off). Using internal fuel the tank can travel about 500 kilometers on roads. Each battalion of T-84s (usually 30-40 tanks) has a maintenance company of at least a hundred mechanics and technicians to assist the tank crews in keeping the vehicles operational.
The Ukrainian Army, now with several years of experience fighting the Russians, reports that most of the high-tech features of the T-84 are not needed in the Donbas fighting but could perhaps be useful if Russia brought in equally advanced tank designs. What the Russians really need is more and better motivation but that sort of thing has proved hard to come by in contemporary Russia. This is the sort of thing that repeats itself again and again throughout history but is generally played down these days in favor of neat new tech.