Alice sends a message to a new address A1, not to Bob's ID key. This new address is derived from the DH ratchet, known only to Alice and Bob. Bob pulls messages sent to A1 from the relay and then decrypts them.
Alice sends a message to a new address A1, not to Bob's ID key. This new address is derived from the DH ratchet, known only to Alice and Bob. Bob pulls messages sent to A1 from the relay and then decrypts them.