$SYS topics on 2nd level

[Tim Kellogg <tim@2lemetry.com>]

Hi,

The 3.1.1 spec says that “#” subscriptions should not receive messages from topics starting with “$” as the first character of the topic.  At 2lemetry, our broker uses $SYS topics the same as Mosquitto does, except that “$SYS” is on the 2nd level of the topic. For instance, “com.example/$SYS” gives metadata for topics under “com.example/#”.

I think it would be appropriate to make the clause more generic, to include 2nd level $SYS topics.

Tim Kellogg

Sr. Software Engineer, Protocols

2lemetry

605-593-7099

@kellogh