UGGGG... :-( Questions like this just make me realize that the marketing retards have really won the minds of some.
What is SIP v2 really? The first officially released version of the SIP RFC was 2543. This was refined to the more modern RFC 3261 so is this SIP v2? If there is no RFC to define it then it doesn't exist and is nothing more than marketing fluff. So what defines "SIP v2"?
IP Office supports the following RFCs. Take a look at any "SIP v2" device and find out what RFCs they support and compare then see if any that they might support that we do not are important to your application.
RFC 3261 - SIP session Initiation Protocol
RFC 1889 – RTP
RFC 1890 - RTP Audio
RFC 4566 – SDP
RFC 2833 - RTP /DTMF
RFC 3264 - SDP Negotiation
RFC 3265 - Event Notification
RFC 3515 - SIP Refer
RFC 3842 - Message Waiting
RFC 3310 – Authentication
RFC 2976 – INFO
RFC 3323 - Privacy for SIP (PAI) and draft-ietf-sip-privacy-04 (RPID)
Kyle Holladay
ACSS SME Communications
ACE Implement: IP Office
MCP/MCTS Exchange 2007
Adtran ATSA, Aruba ACMA
"Thinking is the hardest work there is, which is the probable reason why so few engage in it." - Henry Ford