Messerschmitt Bf.110 in service with the Luftwaffe. Part eleven. The end.

 

The Bf.110H was the last proposed variant of the Bf.110. It was expected to be powered by two Daimler Benz DB605E engines and was going to be armed with two 30mm Mk.108 cannons plus one 30mm Mk.103. It would've equipped with bomb racks capable of carrying 2 ETC 500 bombs and either 4 ETC 50 underwing bomb racks or 4 Nebel Werfer 21cm rocket launcher.
There were also some proposed variants like H-4 night fighter equipped with radar and the H-5 heavy fighter. Some sources also state that an H-3 variant was expected, for reconnaissance duties and was to be armed with four 7.92mm Mk.17 machine guns instead of the Mk.108 cannons. Unlike its predecessors, it was expected to be a single-seat fighter, except the H-4 which would've required a radar operator. The removal of the observer/radio operator would've provided a performance improvement.
Work on the Bf.110H began in 1943 (though, according to some sources it was one year earlier, in 1942). In February, the first prototype was almost complete, however, on 24th February the USAAF bombed the Gothaer Wagonfabrik, which was leading the Bf.110H project and destroyed both the prototype and test facilities. This set the project back for at least six months. In September 1944 its development was cut short and, shortly later, in November, the Bf.110H was not included in the Emergency Fighter Program. 
According to some sources, it did reach production status with some very few machines produced, however, there are not proofs of that having took place, and it was most likely, destroyed before it could reach production.

The last major combat for the Bf.110 took place in early 1945 when acting as radar-equipped night fighter defending the Reich against Royal Air Force's (RAF) bombers.
Major Heinz-Wolfgang Schnaufer, history's top-scoring night fighter ace with 121 night victories, almost all of them in the Bf.110, flew hist last major combat action on the night of 21st February 1945 in a Bf.110G-4 equipped with Schräge Musik upward-firing cannons and Liechtenstein radar. He managed to intercept a formation of Avro Lancaster bombers and shot down seven of them in less than twenty minutes.
Production of the Bf.110 ceased officially in March 1945 with almost 6,000 units built throughout the war and the remaining operational aircraft were surrendered to the Allied upon German capitulation in May 1945. One was captured by the British forces at Grove airfield, in Denmark and is nowadays on display at the RAF's museum in London.

Sources:
1st https://www.historyofwar.org/articles/weapons_bf_110H.html
2nd https://en.wikipedia.org/wiki/Messerschmitt_Bf_110_operational_history
3rd Histoire & Collections - Avions et Pilotes 11 - Messerschmitt Bf.110 & Me.210-410 1939 -1945
4th Signal Squadron - Aircraft In action 1030 - Messerschmitt Bf-110 Zerstörer in Action