for x in txn.iter_rev_remote(&remote_ref.lock().remote, None)? {
                let (_, p) = x?;
                let h: Hash = p.a.into();
                if txn.channel_has_state(txn.states(&current_channel.read()), &p.b).unwrap().is_some() {
                    break
                }
                if txn.get_revchanges(&current_channel, &h).unwrap().is_none() {
                    to_download.push(CS::Change(h));
                }
            }
            // The patches in theirs_ge_dichotomy are unknown to us,
            // download them.