You don't have to start and stop IHS. Only thing you need to check if this fix updated context root for application , then you will have to generate plugin and propogate it to webserver , if this is not fix then you might have to get back to developer to get it fixed, but just to make sure that webserver have no affect .
Give developer direct application server url and ask him to validate , if it is not working then the fix they provided is not correct.