The project is no longer being maintained. If you are looking for a well supported solution, please use MailKit. It's great!
A cross-platform IMAP library for .NET, supporting .Net 2.0 - 4.5, Mono and Windows Phone
The documentation is currently available at https://imapx.org/docs/ or https://github.com/emuuu/imapxDocumentation
Originally developed by Andriy Mykhaylyuk, refactored and extended by @azanov