Search for messages not containing text

How do I specify that I want to search for a message not containing text?  There doesn’t seem to be anything in the docs to indicate how to do this


I don’t think there is a way of searching for messages without text directly, but perhaps you can get closer to what you want by selecting only really small messages, messages with attachments, etc. 

Sorry, I don’t mean not containing any text, but rather messages that don’t contain specific text.

I am afraid that this isn’t possible either. I will suggest it to our developers, perhaps they will be able to implement it in future updates.