AT+QMTCFG=? return error

Hi I am trying to use EC25(also I have EC20 too.) MQTT function.
But when I send AT+QMTCFG=“rev/mode”,0,0,1 , it return fail.
And I send AT+QMTCFG=?, also return error.
Is it mean dosen’t support MQTT?

Here is the ATI info, and I do this on computer throught USB port
Revision: EC25EFAR02A06M4G

Hello wols_yang, thanks for your question on quectel forums
We do not support MQTT function in this version EC25EFAR02A06M4G, this is a very old version. We have already supported it in the later version. Because it is a cross-baseline upgrade, the upgrade from R02 to R06 is not supported. You can contact our local FAE and sales to apply for the latest version of test samples by email, thank you.