IRON REALM MAP PATCH (required to enter the Iron continents, and to use flight paths there)
Copy the Data folder from this zip into your World of Warcraft 1.12.1 folder so that
  <your WoW folder>\Data\patch-3.MPQ
sits next to patch.MPQ and patch-2.MPQ. Nothing is overwritten. If a patch-3.MPQ from
another mod is already there, rename this one to the next free number (patch-4.MPQ ... patch-9.MPQ).
Remove it and the game runs exactly as before. It contains three files:
  DBFilesClient\Map.dbc         - lets the client recognize the two new continents
  DBFilesClient\TaxiNodes.dbc   - flight master locations on the new continents
  DBFilesClient\TaxiPath.dbc    - flight path routes on the new continents
