"The court has already decided my case but hasn't notified me about the decision yet. If it is negative, I will have to appeal to a higher Court."
"The court hasn't yet decided my case. If it is negative, I will have to appeal to a higher Court."
In the first case, the speaker knows for sure that the decision has been made, but he doesn't know wether it is negative or positive. So using Present Tense in the if clause of the conditional sentence is logical.
In the second case, however, the speaker knows that the decision will be made in the near future. Yet, according to the grammatical rule, he still has to use Present Tense in the if clause. Can he use Futur Tense and say 'If it will be negative, I will have to appeal to a higher Court.'?