Microsoft Notification Protocol

Microsoft Notification Protocol is a protocol used in the program Windows Live Messenger, as well as in previous versions of this program, known under the names of MSN Messenger and Windows Messenger, and in Microsoft Messenger for Mac.

The latest versions of the protocol are used in Skype's messenger, absorbed by Microsoft and replaced by Windows Live Messenger in 2013.

Several third-party clients, in particular Pidgin and Trillian, supported some versions of the protocol. MSNP was first used in the program MSN Messenger Service in 1999. Microsoft Notification Protocol