For the more recent episodes, I'd recommend checking the official server's website, I think iRO release most of their changes on their patch notes. But you are talking about eps 5~6 that might be as old as RMS (15~ yrs !), I doubt there's any complete record of them.
Another resource, if you really want to dig into, could be some of the old eAthena commit / branches and their notes on changes:
https://github.com/eathena/eathena/branches/all ...