IMSP is Internet Message Support Protocol. Defined in a 1995 Internet Draft, which carries this abstract:

Work on standardizing IMSP was never completed because it was superseded by the ACAP protocol, which provides a superset of IMSP's functionality.

Implementations

• An IMSP server is available for download from CMU.

• The Horde PHP framework and applications have IMSP support.

• Mulberry supports IMSP storage of mail preferences and address books.

• Silkymail (discontinued) supported IMSP storage of mail preferences and address books. Address books were shared with Mulberry.

• Simeon (discontinued) supported IMSP storage of mail preferences and address books.

• An IMSP address book plugin is available for SquirrelMail.

References