...Of course there's the possibility of splitting lwjgl in multiple jars, some 1.4 compatible, some 1.5 compatible:
1. lwjgl-core.jar with Display, Mouse, Keyboard and support classes for the other packages (1.4)
2. lwjgl-gl2.jar with GL*, ARB* (1.4)
3. lwjgl-d3d.jar with everything d3d related (1.5 since it will only be used on windows, where we can require 1.5)
4. lwjgl-gl3.jar with everything gl3 related (might as well be 1.5 since mac os x 10.3 will probably never support gl3)
5. lwjgl_util.jar, lwjgl_applet etc. (1.4)
the native dlls might be split up accordingly but it's not as important, compatibility wise.