If you want to leave a session, click on the button in the bottom right corner of the session list.
When you leave an online session, you will join an offline local session that no one else can join.
When you want to join a new session the 'Leave session' button has been switched to a 'Join session' button. Click on it and you will see a pop-up window where you can enter the PIN-code of the session you would like to join.
