Originally Posted by yokos
What are the diffs between sylpheed claws & sylpheed?
Originally, sylpheed was the lean-and-mean mail client, sylpheed claws added more (not-so-tested) features.
From the FAQ
What are the differences between Claws Mail and Sylpheed?
Claws Mail (formerly Sylpheed-Claws) started as the bleeding-edge version of Sylpheed, in order to act as a testbed for new features for Sylpheed. The idea was to regularly resync with Hiroyuki's main branch, and vice-versa. Claws Mail then evolved into the stable extended version of Sylpheed, and is now an entity in its own right, mainly due to different goals and the fact that syncing both codebases doesn't happen anymore.
Claws Mail has many extra features compared to Sylpheed and is more powerful, yet is just as fast, lightweight and stable.
Anyway, sylpheed has all the common options (I use sylpheed myself).