hey guy i came across this update for the diamond while looking for something i forgot what.... maybe we can use it... probably not.
heres the site reporting on the update:
http://wmpoweruser.com/?p=652
which has a link to where this site got the info:
http://www.coolsmartphone.com/news4200.html
and the official htc site which has the update i guess:
http://devicehelp.vodafone.co.uk/diamondupgrade.php