If I add a participant to a Meetme conference using the addParticipant method, the conference.getPendingParticipants() is still an empty list. Where can I find the list of added participants who haven't answered the incoming conference call yet?

Also no callback is triggered when I add a participant to a conference

I believe pending participants are only intended for those that are waiting for a moderator to allow them to join the meeting, not for participants being added. There's no specific list of participants that are being added. But you can look at activeParticipant.getParticipantConnectionStatus() === AvayaClientServices.Services.Conference.ParticipantConnectionStatus.CONNECTION_STATUS_CONNECTING to see if they are in the midst of connecting.

Yes ideally the addOnDataSetChangedCallback should be triggered, but it doesn't look like it does. On the plus side the client knows that it just added the participant.

If the invited person does not accept the incoming conference call, it seems like no callback is triggered. The only thing we get is the following message in the console:

{name: 'UCCPServerError', code: 'fail', message: 'UCCP server responded with fail', type: 'dialoutCompletedEvent'}

Is there way we know that the invite failed and we have to update the participants list again?

addParticipant returns a promise, it should reject in this scenario.

"Yes ideally the addOnDataSetChangedCallback should be triggered, but it doesn't look like it does. On the plus side the client knows that it just added the participant."

The problem is that it takes around 100ms before the getActiveParticipants() list is update, after I have added a participant to the conference. So without callback, the only option we have is to constantly poll the getActiveParticipants(). This will cause unnecessary re-renders and a performance overhead of our application. So is it possible to add a callback for this in the SDK?

It looks like you can add a .progress() handler to the addParticipant promise. That should trigger after the initial response is received from the server and the participant is added.