Re: [mosquitto-dev] Interoperability between V3.1 and V5

[Steve Prior <sprior@xxxxxxxxxxxx>]

Thanks,

I actually did figure that out  after being confused about "P2" meaning v3.1.1.

What I'm most interested in at the moment is the shared subscription/load 
balancing feature.  I thought I might have seen mention that this might work 
with a v3.1.1 client as long as the mosquitto broker supports it - is this 
true?  I've got Arduino/ESP8266 IOT devices which use the PubSub library which 
does not have v5 and won't soon.  It's possible that I'd want some of them to 
publish to a topic that is subscribed to from load balanced handlers, though 
also it sounds like the $share/group/topic might only need to be done by the 
subscriber and the publisher might just need to publish to topic and could still 
be v3.1.1?

Steve

On 8/4/2021 12:29 PM, Roger Light wrote:
> Hi Steve,
>
> The log message on connect is:
>
> New client connected from <ip>:<port> as <client id> (p<protocol>,
> c<clean session/start>, k<keepalive>, u'<username>')
>
> The protocol value currently shows: 5 for MQTT v5.0, 2 for MQTT
> v3.1.1, and 1 for MQTT v3.1. I'm fixing that so it will be 5, 4, and 3
> respectively to match the protocol assigned number.
>
> Regards,
>
> Roger
>
>
> On Sun, 1 Aug 2021 at 06:08, Steve Prior <sprior@xxxxxxxxxxxx> wrote:
> > With log_type all on a test mosquitto server I don't see any way to determine
> > what protocol version a client used to connect to the broker.  Is there any way
> > on the server to verify that a client is using a given protocol version? This
> > will become important to me later when I try to change the protocol version in
> > the c library from SWI-Prolog.
> >
> > Steve
> >
> > On 7/29/2021 5:39 AM, Roger Light wrote:
> > > Hi Steve,
> > >
> > > That's correct. The only caveat is that when MQTT v5 clients publish
> > > messages that have MQTT v5 properties attached those properties won't
> > > be passed to the v3.1/v3.1.1 clients of course.
> > >
> > > Regards,
> > >
> > > Roger
> > >
> > > On Thu, 29 Jul 2021 at 06:28, Steve Prior <sprior@xxxxxxxxxxxx> wrote:
> > > > I'm starting to move from v3.1 to v5 and wanted to confirm that v3.1 clients can
> > > > interoperate with v5 clients through Mosquitto (both sides can publish and
> > > > subscribe to the other versions messages), correct?
> > > >
> > > > Steve
> > > >
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