Important note about disappearing messages: Any existing chats will now expose and actually respect the expiry period (if such is set). The “delete timer” for any old messages start when you open the chat with expiring messages and see the messages (again) – this means that old messages and attachments are not deleted until you open the chat. The expiry period is saved per-message, so history is obeyed in that sense.
This behavior gives users opportunity to save the attachments out of the messages (open the attachment and select export from top pulley menu) before they are deleted with the message – this is something Signal clients lets you do as well.
This is an important feature Whisperfish should have supported a long time ago, but all the puzzle pieces fell into place only now.
If you’re worried about losing data because of disappearing messages, making a backup of Whisperfish data folder is always a good, well, backup!
And as always, please report any issues and bugs you find!