First I have noticed many times that an entry of an item to the guide has many similar items already in it. How can we distinguish the latest entry from the established entries? I would suggest dating the entries when entered.

Please provide an example. We do track when an item is added to the ChipGuide and the last time it was modified.

Second what would be the definitive date for an older currency verses an expired or obsolete currency? I have seen some dates like 1927 and then another 1924 that doesn't say older currency.
Thank you for reading my questions

Older currencies mean currencies that are no longer in use. For example, in the European Common Market countries the Euro is used. The older currencies are the legacy currencies like the Lira and Deutsche Mark. Note that originally the ChipGuide did not have a separate category for older currencies, some items might need to be updated.