Lemonade Profile
The Lemonade Profile is a set of protocols and mandatory extensions which provides email access to diverse environments, including mobile handsets and other resource constrained devices. It is the product of an IETF Working Group, and is largely based on pre-existing specifications, including IMAP and the Message Submission profile of SMTP. It was first published in 2006 as RFC 4550, and updated in 2009 as RFC 5550.