Compatible between SI and vanilla

I've seen a few mods that have seperate parts for SI and Vanilla Oblivion. But i've also seen ones that say they are compatible for both without different versions. If I change/edit values in oblivion.esm (which includes vanilla and Shivering Isles), will that mod work properly for someone without Shivering isles?

If not, what is the easiest way to create a mod for both?

A mod only requires SI if it uses something from SI - one of the items, abilities, spells, etc. Speculations if you do modify something from SI - I have a feeling that if you add a SI item to a levelled list (from non-SI Oblivion), then load the game without SI, the item simply won't appear. However, if you modify the SI item then the user will probably need SI to load your mod (as mods hiccup in the CS whenever an item is missing). I think you can tell SI items, quests, etc. because they all have SE or SI in front of the name.

Likewise, the same goes for the different CS versions. If you use one of the CS v1.2 functions, or Touch-Explode (and maybe a few Magic Effects?) then users will have to have the later Oblivion patches (v1.2) to use it.

--Haama 18:52, 2 November 2007 (EDT)

To add some more info for the scripting side of it

• If a script mentions an item from SI it will not run in-game. It will start running once the player installs SI.
  • This might be true for most EditorIDs, however quests don't seem to cause the problem.

--Haama 12:00, 26 February 2008 (EST)