MQTT sample supports which version of mqtt and tls

[User_PP]

I was successful in building and running the MQTT sample. 

But now I am curious as to which MQTT and TLS version is the sample connecting to?

is it MQTT V5 and TLS 1.3?

if not can I connect to these version MQTT brokers?

I am using the test.mosquito.org mqtt broker for MQTT over TLS with certs produced by me

[Susheel Nuguru]

Hello,

Since you have linked to NCS 2.3.0 sample docs we assume you are using that version.

According to the MQTT library documentation it uses MQTT 3.1.1 by default and you can also use 3.1.0

On the nRF9160 SiP product page under product brief it says "Integrated TLS(1.2)/DTLS(1.2) and TCP/UDP/IPV4/IPV6 Dual Stack"

Not really sure about the compatibility between different versions

[User_PP]

So you are saying that nordic doesn't support v5?

[Susheel Nuguru]

There is IPv5, The next version after IPv4 is IPv6

[User_PP]

I meant MQTTV5 and TLS 1.3 not IPV4 or 6

[User_PP]

Can someone reply to this query?

[Eivind J]

The MQTT sample is using the Zephyr MQTT library. Based on its documentation (latest) it only supports MQTT v3.1.0 and v3.1.1, as stated by Susheel Nuguru .There is an issue to add support for it in Zephyr, although it doesn't seem to be prioritized. 

The default in the MQTT sample is to use MQTT v3.1.1 in NCS 2.3.0 (see protocol_version in struct mqtt_client). 
The nRF9160 does support TLS and DTLS v1.2 (see socket protocols in nrf_socket.h), but not v1.3.
So you'll need a broker that support MQTT v3.1.0 or v3.1.1 and TLS v1.2. test.mosquito.org should support this.