On Tue, Sep 4, 2012 at 3:56 AM, Herbert Valerio Riedel <hvr@gnu.org> wrote:
I've been wondering whether it might be useful to add a feature to
Haddock similar to what can be found in other API documentation systems,
specifically an optional parseable "since"-attribute, declaring the last
package version when the associated definition/symbol was introduced or
its semantics modified.

I think it would be very useful. We don't have any way of specifying identifier-level attributes right now that I know of, and such a capability would be helpful beyond just this use, too.