I would not worry. Step 5 is the only one you should use. I seem to remember that there were either no changes or only cosmetic changes between 4 and 5. that's not surprising given that step 5 is just each region publishing the final agreed text of ICH. So for instance the EMA had an implementation period on the front. The FDA just put the date they published it (which was later than EMA!).
Thing to watch out for now is R3!!!