Yes, we do! An in the exact order they were sent!
But you must use the publish method to send your messages and the subscribeWithBuffer (or subscribeWithOptions) method to subscribe the channel.
This will create a buffer for each subscriber (identified uniquely by the subscriberId parameter) so the Realtime server knows exactly which messages were properly delivered to that subscriber.
When users lose their connections, the Realtime server will flush their buffers as soon as they reconnect again, sending all the messages not yet received.
You can control the message retention time for each published messages through the TTL parameter of the publish method (maximum 2 minutes for Free plans and 3 days for paid plans).
Learn more about the Realtime Messaging delivery modes at http://messaging-public.realtime.co/documentation/starting-guide/delivery-modes.html
This new delivery method was publicly launched in February 2017.