Install the latest version of Letter Opener
This message can appear after a system update and simply requires the latest version of Letter Opener.
Get the latest version from our download page.
To ensure that Mail functionality is not compromised by outdated plug-ins, Mail disables plug-ins that are not updated.
We provide a newsletter to inform our costumers about important updates.
- Go to Mail > Letter Opener for macOS Mail > Newsletter Sign Up
- Enter your email address and click the Join button.