Accept invite for muc?

Hi,

I am able to create muc and invite users to room. I have one confusion.

Let's say there are 2 users.

User1 creates room and send invite to user2. I am able to do this.

My first question is

#01. How user2 will receive invite from user1? (I am using smack 4.1.0 rc1  and it doesn't have addInvitationListener method so please suggest similar to this)

#02. Once user2 get invite to join room, how can user2 join room?