http://www.freewebs.com/masterpikachu/ZC%20Content/untitled.qst
This test quest file you see here is for ZC 2.10. In this quest file, there is a passageway warp on a DMap whose level is 0. The passageway warp works perfectly fine on level 0 DMaps in 2.10 and lower, but if you play this quest in 2.5, the passageway warp no longer works properly since level 0 Dmaps in 2.10 and lower are set to use caves instead of item cellars in 2.5.
This is a game-ending problem in 2.5 if you have to use a passageway warp in order to make progress in a quest that was built in 2.10 or lower.
Perhaps there should be a flag that says 'Allow Passageway Warps', which would automatically be checked for Level 0 DMaps in quests made in 2.10 and lower.
Here's an example of a quest that uses a passageway on a level 0 DMap (particularly the overworld); it was built by Germi in 1.90:http://zeldaclassic.armageddongames.net/viewquest.php?q=124
There is a passageway at the beginning of the quest, where the candle is used to burn a tree. You have to go through it in order to get to any other screen on the overworld map. The passageway not working properly makes the quest unplayable in 2.5.
PS: Due to the fact that passageway warps don't work on DMaps that use caves instead of item cellars in 2.5, I came up with the idea of setting up a special room on a screen with a passageway warp, though I had to apply the 'Messages Disappear' rule and set a string for the screen where it is applied.