PubSub message expiration
Does the Tigase PubSub API support message expiration, i.e. the message is not delivered to subscribers after the expiration date? In our scenario some subscribers are offline and we do not want them to receive messages that have expired once they come back online (the standard pubsub scenario would deliver all published messages while client is offline). We still want them to receive offline messages that have not expired yet, once the message is past the expiration date it should not be delivered to the subscriber. What is the best way to implement this? I did not find anything regarding message expiration in the PubSub protocol. I know that XMPP spec has advanced message processing (XEP-0079: http://xmpp.org/extensions/xep-0079.html), but looks like it only applies to peer to peer messages and not to PubSub messages. Can advanced message processing be used for PubSub messages too?