I didn't find how to create an issue in issue tracker so I'm creating this discussion. According to XEP-184 (http://xmpp.org/extensions/xep-0184.html) two client are able to exchange with delivery receipts. From first sign this is not related to the server but then one of participants was offline openfire don't save receipts because of this code from OfflineMessageStore
The patch doesn't work for offline receipts.
Yes, my bad. There is 'not' before checking chatstate namespace. And yes - it should works.
This issue has been fixed on version 3.9.2 but version 4.0.2 has again the same problem.