His friend who is in charge changed his job title; can he accept the increased salary that resulted from that?
Question

I work as a computer engineer in administration, and I received my salary to which I am entitled for having the job title of engineer. But after a while, I noticed that my salary had increased, because of a friend of mine in the financial department who – without my prior knowledge – had changed my job title from engineer to technician, as a result of which my salary increased. When I asked him, he told me: You are entitled to this increase, because you are doing the work of a technician and an engineer. In fact, what he said is true, as I do the work of a technician when required, and I do the work of an engineer when required, since there are no technicians with us in administration. Am I entitled to this increase and is it permissible for me to accept it, or is it haram and not permissible?
Praise be to Allah.There is no reason why you should not accept this increase, and it is halal for you, if you meet the conditions, which are as follows:

This increase should be something to which you are entitled, and you should in fact be doing the work for which you deserve this increase.
The administration system in which you work should allow you to receive this increase, and not prevent that.
Your friend should have the authority to change your job title, and there should not be any lying, deceit or tampering involved in that.

If you meet these conditions, then it is halal for you, but if you do not meet one of the conditions, then it is not permissible for you to accept it, and you should advise your friend to fear Allah, may He be exalted, and to be honest in doing the work that he is given to do.
And Allah knows best.