It was a hoax. The FPSC released a press release saying it is not true.

Even if the decision was true, it does not mean injustice was done to the candidates of previous years. It is simply a change of policy. Just because you would have passed the 2017 exam with the policies of the 2018 exam does not mean the policies of 2017 were unjust. That is like saying I am eligible for the army because 20 years ago one needed 3rd division to be eligible whereas now it is 2nd division or 1st division. It doens't mean the policy today is unjust, it is simply a new policy.