So today I realized that Zero now is developing some weakness in his hind legs. when he jumps down of the bed he looks as if he slipping and sliding and he seems to be having difficulty standing up. Other than that he is the same loveable, purring, happy cat. I looked up the weakness in the hind legs and they do say that it's a sign of the drive form of FIP. it's interesting I cannot find any information on the disease changing from wet to dry FIP, but it seems that that is what happened with Zero. He has no symptoms of wet FIP anymore but now after reducing his steroid medication it seems that he is developing dry FIP symptoms. I'm going to return his steroid medication to the usual today.