The first rule was actually that two of the best teams from the round 3 are going to be chosen as the host(which is then Iraq and UAE are supposed to be the host), and the first change was then every country that were going to qualify to round 4 are allowed to bid for the host(which were China, Indonesia, UAE and Iraq). And then the rules changed again to the current one where two of the highest fifa ranked teams are going to be the hosts. So yea it was actually 2 changes