Posthumous promotion is permissible to the survivors of a person who dies in duty. Posthumous promotion can be either financial or historical and both cases are also permissible.
Dr. Monzer Kahf, a prominent economist and counsellor states the following: The effect of the posthumous promotion is either financial or historical. In both cases it is permissible: Giving extra pensions to the survivors of a person who dies in duty is allowed in the Shari`ah, and honouring the memories of such persons and glorifying their actions is also permissible. Of course, as long as this is done with justice, by treating them equally and without false exaggerations or extra glorification that comes close to a certain form of worshiping.