I’m reposting this from the Classic Tech Support forums:
I’ve been trying to develop a custom map in the world editor, and I started by just loading up Twisted Meadows and then saving it as a separate file. This is in classic mode, not Reforged.
After working on this map for a little while I’ve noticed that it isn’t actually up to date with the latest patch, for example some stats aren’t consistent and I think it may be before the the Cloak of Shadows was changed to work during both night and day.
As far as I know the rest of the game is totally up-to-date; I think it automatically does this as it is always online?
Is there a way to create custom maps with the editor that are actually at the current patch?
p.s. OT I haven’t been able to disable formations in game either; the game crashes when I try to save that change in settings/options. Any ideas?
When you make changes to a map it starts using a custom data set. This is not a bug, it is an important feature.
To change this: Scenario → Map Options → Game Data Set
Finally, the game is not always online. It only requires you log in once every 30 days. You can always play single player, even with no internet.
Okay, but when I opened this map and saved it, my game was up-to-date with the current patch. The map just defaulted to a much older patch. I don’t know if changing the data-set to melee/current is going to then wipe my own edits to units/triggers etc. Or what happens later if a new patch comes out?
Thanks for sharing about the game options though 
The purpose of not tying your custom map to the most recent patch is to avoid your data be altered. As long as you use that, it won’t change.
I think custom maps are like a snapshot in time, and will not get the latest patch updates, only ladder maps do. For example you made a map where the gloves of speed give 30 attack speed, and in the next patch they are changed to 35. Your custom map will retain the 30 attack speed version because now it treats even the standard items as custom, and it will never change them unless you manually update it. The only workaround for that I can think of, is instead of using standard items and expect them to update, make a copy of them as custom items that you can keep a track of and update independently of patch changes.