I was recently told that the serving rules have been changed. Supposedly you're now allowed to have the racquet head above the waist line, as long as the head is below the wrist. Bogus or truth? I suppose the former, because I found no reference to such a change anywhere.

Told by whom?

I think that person is talking rubbish.

It may be in reference to the "experiment" that the IBF is conducting with some new rules.
for more info search on this site or worldbadminton.net

If u've seen lastest official badminton games. The empire will call faults when the racket is above the waist.

Of course this cannot be because this way you are able to serve a smash..so long as ur wrist is over ur head (Which it is if you are doing it correctly)

Immediately do a backhand smash for a serve. Hm, don't quite fancy that.