Re: [mqtt-comment] MQTT v5.0 RETAIN optional

Hello,

I agree with Christoph, retained messages are an important part of MQTT. Making them optional is a regressive step and reduces interoperability.

Cheers,

Roger

On 14 Mar 2017 12:04 p.m., "" <> wrote:

Dear committee members,

I may be a bit late in the process, but I am very concerned about the future direction of MQTT:

RETAINed messages have always been a key feature of MQTT and are substantial for applications which

do not want to implement a secondary transport to modify or query status information.

Your current working draft #11 shows the broker support of RETAINed messages and wills as „MAY“ while 

MQTT3.1.1 insists on a „MUST“ for a broker to be compliant.

I know that a number of major IoT platforms decided not to make RETAIN available over MQTT

(e.g. AWS IoT, IBM IoT Foundation Services).

Please review your decision to make support or RETAINed messages optional. Otherwise I see

- interoperability issues between applications and brokers (think bridging)

- more complex client application

- a decrease in the use of MQTT

Cheers

Christoph Krey

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