Message storage for offline recipient

If I send a message but the recipient is offline, then the xx network stores it somewhere until the recipient comes online. Where are messages stored in this case? How long are messages stored awaiting retrieval? Is there a guarantee of storage time?

I am not looking for a detailed answer here. I can read technical documents. Please post a link to the technical document which describes storage of messages when the recipient is offline. Thank you.

Where are messages stored in this case?

  • Messages are stored in the database of gateways.

How long are messages stored awaiting retrieval?

  • 500 hours (~3 weeks)

Is there a guarantee of storage time?

  • Messages sent during a specific round are stored in each of the 5 nodes’ gateway that processed the round.

Please post a link to the technical document which describes storage of messages when the recipient is offline.