The user-friendly, lightweight, and fast email client Latest Release: 3.17.3 (News), on 22 December 2018

The vCalendar plugin

The vCalendar plugin provides groupware features for Claws Mail, namely: The calendars and events are displayed in a list, in the same way that Claws Mail displays your emails.

libcurl is required,

Here are a few screenshots illustrating the features: