Although the A and E models were to have been delivered at the same time, the Jumo engine was still not ready; the first Jumo powered Ju 188 A-1 versions were shipped only shortly after the BMW versions, albeit at a much slower rate. By the time deliveries were finally picking up in late 1943, the Jumo was available in a new MW 50 methanol-water injection "boosted" version that delivered for takeoff. With this engine, the planes were known as the Ju 188 A-2 and started deliveries in early 1944.