Each linked device in multi-device treats each other as a different recipient. Encrypted messages are kept on server until they are received by the recipients. For each linked device, the server holds a queue of 1000 most recent undelivered messages so the device has to come online often enough to prevent overflowing of queue. The server also deletes undelivered messages that are older than 60 days even if the queue is not full.
Each linked device in multi-device treats each other as a different recipient. Encrypted messages are kept on server until they are received by the recipients. For each linked device, the server holds a queue of 1000 most recent undelivered messages so the device has to come online often enough to prevent overflowing of queue. The server also deletes undelivered messages that are older than 60 days even if the queue is not full.