things should be for the current version. v1.11 now, something else in the future, if they continue doing patches with major changes. Since a number of the pages in the wiki now are rough drafts that were pasted over from old site content, written during v1.09, those pages need updates both large and small.
v1.09 info is still useful since there are always people using older patch versions, but it should be identified as such. I've added disclaimers to a few of the older pages, the TCs and such, and put a v1.09 category tag on some other pages also.
Generally speaking, if it's just a small mention here or there on a page, then update it. If it's a whole page of stats or info that are about v1.09, then save it. name the page appropriately, if possible. note the 2 item generation tutorials, for instance.
http://www.diabloii.net/wiki/Category:Item_Generation