Claws Mail is an email client based on GTK+. Besides an email program it also has plug-ins, like a calender or a RSS system. The supported protocols are POP3, SMTP and SSL/TLSv1. If you want to use the program you have to install AmiCygnix v1.0 (or higher) first. Claws Mail and AmiCygnix can be downloaded from the OS4 depot.