Some information is definitive, some is hastily put together and incomplete. Both are useful to readers, so do not be shy to put information up which is incomplete or out of date -- it may be the best there is. However, do remember to state what the status is. When was it last updated? Is it complete? What is its scope? For a phone book for example, what set of people are in it?
Not every document needs a status declaration, if there is something in the overview page of the work which covers it.
You can of course also give a feel for the status of the text by its language ... bad spelling, missing capitals, and relaxed grammar all indicate informal notes. Careful use of verbs such as "shall" and "should", and the introduction of Long Capitalized Noun Phrases (LCNPs) will give at least the impression of an ISO standard. ;-)
In some cases it can be useful to put creation dates and last modified dates on your work. (Note that this is the sort of thing which one could make a server do automatically with a little programming).
Figure out whether putting one might later save the reader from following out of date information.