sentences:  Once the receiver had been moved to a tail extension, the government tested the missile on the MiG-23 and MiG-23B between 20 March 1970 and 3 October 1973. and it entered service in 1973.A laser-guided version of the Kh-23, the Kh-25, became the basis for the AS-10 'Karen' family of missiles.Technology from these was 'backported' to the Kh-23 to create the Kh-23M in 1974.