Game Feature Independent
One major problem are new features or changes in game flow that haven't been considered in existing maps. The development is going on and nobody wants to constantly update all the old maps. Some changes might be simple and the maps still work and is playable but if we think about new building and restrict the abilities of the old ones or about logistics we come very fast to the conclusion that old maps can't simply be moved to new game versions.
To solve this the map must contain information about the game features it uses and needs. With this information the game could enable or disable certain features to make the map playable the old way. The easiest way to do this is a flag word.
Which new features needs a flag must be decided from case to case. The only thing what we have to define now is that all extra features as disabled with a '0'-flag. This means that all new and yet unknown features will be disabled for old maps and must explicitly enabled for new ones. This guarantees a high compatibility level and full freedom for new flags and features.
Possible feature extensions might be:
- logistics, fuel and ammunition
- buildings only usable by or restricted to certain units like airfields, harbours, etc.
- Special buildings like roads, rails, bridges which might be build or destroyed during the game
- ...