JPim is an email and contact management tool which offers auto-completion for recipient addresses, viewing of plain and HTML email, viewing of email headers, adding of attachments to email and saving attachments received, full contact management features, an easy to modify quick contact list, and the ability to reply to and forward email.
KONSEC Kolab Server is a highly scalable, cluster-capable messaging and collaboration server that is based on the outstanding open source project, Kroupware. The KONSEC Konnektor is a simple client extension that gives Outlook complete group functionality through the Kolab Server, which employs the open standard IMAP together with ACLs, thus enabling you to collaborate in a unique mixed Windows/Linux environment.
Klingofox wapMail is a WAP-based IMAP email client. It was primarily developed and optimised for Treo 600 for Palm and PocketPC XDA/MDA, but should work with any other WAP device. It supports multiple user logins with login/password protection, multiple mail folder functionality, and the ability to compose, delete, and reply to email messages.
Knight's Mail is a Web mail application that uses XUL to render the client display. Its goal is to look and feel as close to Mozilla Thunderbird as possible, while maintaining the positive qualities of a Web mail client such as keeping settings on the server and only requiring a (Mozilla-based) browser to be installed on the client.
Liferay is an enterprise portal. It handles users and portlet drawing, has a full administrative interface, supports all the major databases and the main J2EE application servers, and has single sign-on capabilities and multiple language support. It uses Apache Lucene for document searching. A number of portlets are included, including a guestbook, a calendar, a mapping utility which uses Expedia, news, polls, a document library, and live stock information.
MFilter is a replacement for maildrop/procmail and fetchmail/getmail. It is an email retriever that supports Maildir or command delivery and processing. Its secondary goal is to facilitate the life of the network administrator by centralizing the downloading, filtering, and classification of mail in a simple and flexible way. Some of its features include XML file based configuration and logging of each action taken.
MH-sync is a small suite of command-line tools designed to allow an MH user to read mail offline by synchronizing a local set of MH folders with the "real" MH folders online at a remote site. Changes made using 'rmm' and 'refile' will be propagated back to the server site correctly without being affected by "folder -pack" or server-side message filing or removal. ssh is used as the transport, and no other ports need be open on the firewall.