That's not correct. Word has never had such an option, but has had an option to update links automatically. Whilst links use fields, not all fields are links. There are numerous fields a user wouldn't want to update automatically, including ASK & FILLIN fields.
Some years ago, MS did change the update of
some fields that previously updated automatically in the body of the document, but not all. Fields that do still update automatically include most fields ordinarily used in page headers/footers (and this includes certain fields that don't update automatically when in the body of the document).
And yes, there is an option that updates all fields automatically if any of them change - its any formfield that has the 'calculate on exit' option checked. Of course, you wouldn't want to use one of these in most documents as the forms protection that these require severely restricts editing.
No, for the reasons explained. What is possible, though not necessarily advisable, is to add macros to, say, Word's Normal template to trigger the field updating any time a document is opened or saved. A macro that might be used in the Normal template's 'This Document' module is:
Code:
Private Sub Document_Open()
ActiveDocument.Fields.Update
End Sub
but even this will only update fields in the body of the document.