While the mobile SDKs do not limit the number of people who can join a room and there are no APIs on the mobile SDKs to that effect, we do have protective limits in place to prevent the formation of more Peer Connections than a mobile devices' resources can generally handle.
Currently, the maximum number of remote Peers that the SDK can connect to has a default value of 4, meaning that up to 4 remote Peers can connect with the user.
To change this number, use the Android SDK's setmaxPeers property
SkylinkConfig config = new SkylinkConfig(); // Allow 5 remote Peers to join: config.setMaxPeers(5);