# Release 4.0.4 - (Oct 15, 2020)
* new feature: "Cancel tx" (#6641). The Qt/kivy GUI allows cancelling
an unconfirmed RBF tx by double-spending its inputs to self.
I haven't update to Electrum 4.0.4 yet, but hopefully there's short explanation about it or some people will assume Bitcoin transaction could be canceled.
Is it safe to update it to 4.0.4?
So far no one reported bug on Electrum version 4.0.4, so it should be safe as long as you update it correctly (download from official and verify it's signature).