in conference every user is able to communicate without any trouble but when any user quit the conference room and re join the same room he is unable to see his chat all other users data is available but if any one was re join the room his chat data was not shown.
There is generally no file transfer in xmpp. But there is some share a link to file standard, but Spark doesn’t have that and i’m not sure if Openfire has that either.
I don’t think you understood correctly what i meant. I was talking about XEP-0363: HTTP File Upload
When this feature is implemented, it does uploading onto server and provides a link in the chat automatically behind the scenes. But as i’ve said Spark doesn’t have that.