According to the new Trading protocol described here

github.com/bisq-network/proposals Issue: Trading protocol v2 without arbitrators This is a Bisq Network proposal. Please familiarize yourself with the submission and review process. TL;DR for the initiated Here is a short... was:approved

a new in-app messaging system will be introduced.

However such a system won’t solve the problem that the seller may forget the trade and so forget to release the coins after he has received the money. With this in-app messaging system it would not be possible for the buyer to notify the seller that he has to release the Bitcoins if the seller does not start the Bisq application after he has taken the trade and the money has already been sent to him. Such a case really shouldn’t take the long way through the new Bisq DAO resolution process.

To mitigate this problem a notification mechanism out of the Bisq system would be helpful. A simple solution would be the possibility to add a contact information (e-mail address) in Bisq that will be revealed if the trade has expired. A more complex solution that will protect privacy would be that this message is sent through the Bisq application itself including PGP encryption etc.