The changes have affected the army, navy and military intelligence ranks.
Kenya Army commander Lieutenant General Robert Kibochi has been appointed the Vice Chief of Defence Forces replacing Lieutenant General Joseph Kasaon.
According to The Star, President Uhuru Kenyatta accepted Kasaon's resignation on medical grounds.
In the raft of new changes, Kibochi's deputy, Major General Walter Raria takes over as the new Kenya Army commander.
Kenya Navy's Major General AS Farah will become the director of military intelligence replacing Major General Charles Mwai.
Head of special programmes at the Defence Headquarters Major General Thomas Chepkuto will take charge at the Directorate of Military Intelligence (DMI).
KDF spokesman Colonel David Obonyo was promoted to the senior rank of brigadier and appointed the deputy DMI. Obonyo will be replaced by Paul Njuguna who was his deputy.
The 2010 Constitution replaced the Kenya Armed Forces with Kenya Defence Force, with the Chief of Kenya Defence Forces replacing the Chief of General Staff.
According to the military's internal administrative rules, the CDF retires at 62 while lieutenant-generals and major-generals retire at 58 and 56 respectively if they are not promoted to the next rank.
The rules are applicable to the CDF, the commanders of the Kenya Army, Kenya Air Force and the Kenya Navy.