Hello Sabatino,
I see you had a ticket a couple months ago, and we escalated this issue to the development team for their review. The update we received was that the chat history is the responsibility of the client, and not handled by SmarterMail. However, I would like to apologize for the misunderstanding, as we recently learned that SmarterMail does have an issue with the handling of the chat history.
When using XMPP, the client and server communicate using XML. When a message is sent, most clients just send the message content as plain text, requiring special characters to be XML encoded. In recent weeks, however, we became aware that there are some clients that choose to wrap the message body as CDATA, which allows them to skip the XML encoding. Unfortunately, the code in our current release doesn't properly read the CDATA, so it ends up just logging the time and sender of the message without the message body.
We are working to correct this issue in a future build. I will reopen your support ticket so we can provide you an update when that fix is available.