basysKom announced that their SIP program kcall has been ported to Decibel, making it the first real world application actually using Decibel. But there are still no information available about the state of kopete.
Decibel was developed to provide a central interface for real time communication in KDE 4. The idea is that on the one hand users will be able to manage everything in one place while on the other hand developers can use the APIs provided by Decibel to integrate their program fully with this central place.
Technically Decibel uses the Tapioca which in turn implements the Telepathy specifications. This by the way should make it quite easy to share resources with other Telepathy implementations like they are planned for Gnome.
So Decibel is the Phonon for VoIP and IM. And like Phonon it would be worthless without a real application using it. To do that kcall, a kontact integrated SIP solution,
was ported to Decibel. This is good to see because it gives the Decibel developers feedback about API quality and application needs.
However, the most often used IM application on KDE is kopete. And the idea behind Decibel was that applications just like kopete switch over to use Decibel to be able to concentrate on the app only instead of implementing yet another protocol.
But there seem to be problems. First of all, Decibel won’t be ready for KDE 4.0, but for KDE 4.1:
I rather doubt that we will meet the KDE4.0 deadlines (is it even possible to still add apps to that release at this point?), but I am positive that we can get into KDE 4.1.
Second, kopete itself won’t be ready for KDE 4.0 as it looks like.
On the other there is the techbase entry about kopete which has been written by Mlarouche, the lead developer of kopete. The page sets the aim of a 4.0 release and lists several features. Decibel is supposed to be integrated as a plugin for 4.0 and fully supported as the main backend for 4.1.
So at the moment the situation around kopete is still unclear. I would like to see a version ready for KDE 4.0, but not necessarily as a part of kdenetwork but maybe as part of extragear. Amarok and others have a healthy live there, and I think kopete could benefit in similar ways. But that’s up to the developers.