[rabbitmq-discuss] Client vs Server version

[Matthias Radestock]

On 07/05/13 07:58, Tim Watson wrote:
> Technically it is possible to run disparate versions (the AMQP 0.9.1
> protocol hasn't changed between them after all), but I would strongly
> advise you to use the latest version with the latest server.

Actually, there really is no compelling reason to run the same versions. 
The fact that client and server can be upgraded independently is one of 
the strengths of AMQP.

> Not only have important bug fixes been introduced in the client
> libraries between releases

...which is a good incentive to run recent version. But they don't have 
to be the same as the server. E.g. it is perfectly ok to run the latest 
clients against an old server (as long as it's >=2.0.0 and hence speaks 
AMQP 0-9-1) if, say, the latter is harder to upgrade for operational 
reasons.

> but it's possible in some cases that non-standard
> features (i.e., enhancements to or divergence from the AMQP
> specification) have been added to (or deprecated from) the broker and
> the client might need to be aware of these.

None of these changes affect client library compatibility per se, though 
they may - in some very rare circumstances, e.g. the removal of the 
'immediate' flag you mention - affect applications. But in those cases 
it's really the applications that need updating.

Matthias.