How does EQ2 determine if a window is compatible with game?

[Landiin]

Originally Posted by RH_Warrior

Hi all,

I'm looking at updating an old tradeskill window to the current game version, it's outdated (worked before RoK expansion). Been studying the diff files listed on this site trying to figure out the proper form for an LU41 version, but no luck, EQ2 keeps telling me it's not compatible, and not much else. =/

Basically want to hack it into a working state as fast as possible, failing that, touching up an up-to-date window to look how I want (mostly colours).

So, what does EQ2 look for when determining compatibility?
Any insight is welcome.

Thanks in advance!

PS. I have tried searching in a few ways to find existing info here, but have not so far.

The version attribute of the windows root node.