# Table of contents:

• Introduction
• Command information
• Known changes
• Client-server communication examples
  • Older protocols
  • Newer protocols

# Introduction

CVR0 is a subprotocol of the Mobile Status Notification Protocol. It was introduced officially in Client Version 1.0.0863, along with MSNP2.

It is used for requesting the latest client information in case no other protocols were supported.

# Command information

It introduces the commands:

• CVQ

No error codes were known to be introduced in this version

No commands were known to be removed in this version

# Known changes

(from Beta 2):

• Changed CVR to CVQ
• CVQ: Added fallback URL to response (parameter 5)
• Since MSNP4: Added an empty parameter that is meant to be the client codebase identification parameter added in CVR (parameter 7)
• Since MSNP8: Fixed client codebase identification parameter (parameter 7) to be no longer always empty, and added current user handle to request (parameter 8)

# Client-server communication examples

# Older protocols

Only in MSNP2 to MSNP7, example using Client Version 1.0.

C: VER 1 MSNP2 CVR0
S: VER 1 CVR0
C: CVQ 2 0x0409 win 4.10 i386 MSMSGS 1.0.0863
S: CVQ 2 5.0.0537 5.0.0537 1.0.0863 http://download.microsoft.com/download/msnmessenger/install/5.0/w98nt42kmexp/en-us/setupdl.exe http://messenger.microsoft.com

Server disconnects client.

# Newer protocols

Since MSNP8, example using Client Version 6.1.

C: VER 1 MSNP10 MSNP9 CVR0
S: VER 1 CVR0
C: CVQ 2 0x0409 winnt 5.1 i386 MSNMSGR 6.1.0211 MSMSGS example@passport.com
S: CVQ 2 7.0.0813 7.0.0813 6.2.0205 http://msgr.dlservice.microsoft.com/download/5/d/9/5d9bb5b2-49c7-4890-94ab-d1d5e44a0e6d/Install_MSN_Messenger.exe http://messenger.msn.com

Server disconnects client.