PZL.23 Karas was a Polish light bomber and a reconnaissance aircraft. Serial production of the A version started in 1936 with a total of 40 planes constructed. B variant, with a different engine, was being produced between 1936 and 1938, with 240 machines finished. Polish Aircraft bomber and reconnaissance squadrons received the PZL.23B planes, while the A variant machines were moved to aviation schools. Karas was the main Polish bomber plane used during the September 1939 German invasion of Poland. PZL.42 was an attempt on creating a modernized replacement for the PZL.23 aircraft. Only one prototype was built in 1936.