I have an issue with the new Twitter client. I'm running on a Torch 9850 with 188.8.131.521. In the new Twitter app, there is a small glitch. In the app, you can link a twitter contact tk a BlackBerry contact. Twitter updates then show in the contact card, which is cool. Thus feature has been present in several versions now. What is different is that in 184.108.40.206, there is no way to unlink or change such link. Bad. I now have a contact linked to the wrong Twitter feed with no way to change it.
if I recall correctly, contact link management is done through the BlackBerry contacts app. Open the contacts, find the contact and edit it. At some point in the card you will see the twitter handle, and you'll be able to either empty it or replace it.
it is the same for other social networks like Google Talk or YahooMessenger.
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