Hello! I accepted to install the Thunderbird update #31.3.0 because the pop-up information window informed me about important security updates (about only these changes!). After this new update it was surprise for me that a new message creating with a new GUI, i.e. fields From, To, BCC, Subject etc were changed. I would like to point out, that you have inform users if new updates contain not only security changes but new GUI, new buttons, new any functional changes too. If you write about a security changes so these security changes only should be in this update. In ideal, security updates and interface/functionality changes should be separated because not all user would like to change interfaces. Now I would like to ask you how I can return my mail client to the previous version (31.2.0)? How I can return automatically updated add-ons to the version compatible with the previous Thunderbird version? Something like full roll-back. The new interface of emails is not comfortable for me. I belief that not only I don't like surprises like this.