"Mapi is the protocol that Exchange uses to communicate with
Outlook. OpenChange implements it in the form of the 'libmapi'
library, which is designed to be built into any email client.
""Using the libmapi library, OpenChange allows clients such as
Thunderbird, Evolution, KMail and other open-source applications to
utilise the full range of Mapi functionality, including messaging,
shared calendars, contact databases, public folders, notes and
tasks," the Red Hat team wrote in the blog post. "All applications
can now start speaking the same language, regardless of