The KV1's went out of production about 1943. The KV 85 was produced 43-44, and the last KV variant the KV85 was made up to Spring 1944, replaced by the IS-2. Although production ceased they still saw service until they broke down or were destroyed.
The 260th Guards Heavy Breakthrough Tank Regiment, based on the Leningrad front, operated a number of 1941-vintage KV-1s at least as late as the summer of 1944 before re-equipping with IS-2s. KVs saw service in Manchuria in August 1945, and a few KV-85s were used in the Crimea in the summer of 1944. The Finnish forces had two KVs, nicknamed Klimi, a Model 1940 and Model 1941, both of which received minor upgrades in their service, and both of which survived the war. A single captured KV-2 was used by German forces in 1945 against US forces in the Ruhr.