• When we modify a Jabber account, be sure to clear existing supported XMPP features as well as all ProtocolProviderServiceJabberImpl's registration state change listeners because we will recreate OperationSets. Otherwise wrong behavior can happen like two ICE negociations for the same peer in the same time (because we have more than one OperationSetBasicTelephony associated with the account and listen to Jingle packets).