Backwards compatibility

Recordon, David drecordon at verisign.com
Mon Sep 25 19:05:01 UTC 2006


You're right, I believe what Josh meant was that OpenID 2.0 systems MUST
support the 1.1 message format.  Obviously differentiating between the
message formats is possible, and the 2.0 format can be different than
1.1, but a requirement for a 2.0 implementation can be support for 1.1
messages.

--David 

-----Original Message-----
From: specs-bounces at openid.net [mailto:specs-bounces at openid.net] On
Behalf Of David Fuelling
Sent: Sunday, September 24, 2006 3:58 PM
To: 'Josh Hoyt'
Cc: specs at openid.net
Subject: RE: Backwards compatibility

Josh,

Just a point of clarification -- As worded, your #1 says that any OpenId
2.0 message would work in any OpenId 1.1 system, which (from my
perspective) implies that the 2.0 protocol cannot implement any
(significant) message features that aren't defined in 1.1....which would
tend to imply that the two protocols are identical (since 1.1 is already
defined).

Are you really meaning to ask the following instead:

#1R: OpenId 2.0 systems MUST implement and support all of the messages
in OpenId 1.1.

#2R: It is possible for implementations to differentiate between OpenID
1.1 and 2.0 and to construct appropriate messages. In essence, it's a
different protocol, and #1R is not required.



Thanks!

David Fuelling

> -----Original Message-----
> From: specs-bounces at openid.net [mailto:specs-bounces at openid.net] On 
> Behalf Of Josh Hoyt
> Sent: Wednesday, September 20, 2006 4:31 PM
> To: specs at openid.net
> Subject: Backwards compatibility
> 
> When making and evaluating proposals, there have been many references 
> to backwards compatibility. I'm not sure that everyone has the same 
> idea what it means to be backwards compatible.
> 
> There are at least two meanings that I can see:
> 
> 1. Messages that are valid OpenID 2.0 messages are also valid OpenID
> 1.1 messages
> 
> 2. It is possible for implementations to differentiate between OpenID
> 1.1 and 2.0 and to construct appropriate messages. In essence, it's a 
> different protocol.
> 
> I've been focused on maintaining (1). How do you see it?
> 
> Josh
> _______________________________________________
> specs mailing list
> specs at openid.net
> http://openid.net/mailman/listinfo/specs

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