I don't want to raise a bug on Launchpad in case "it's just me" so let's find out.
When I saw the 1.3 release announcement I rushed to update the homebrew package that I maintain for it.
Usually this is as simple as updating the URL and the shasum for the tarball, and running "brew install" to download and compile it.
However, this time things haven't been very smooth. The build failed, and in debug mode I found that it was complaining about the lack of a library "cares" / c-ares which obviously hadn't been a dependency until now. It looks like it is a result of the "Add support for SRV lookups" feature.
I've installed c-ares itself via homebrew and added it as a dependency on my formula, so I'm able to compile 1.3. Hurray! however, I'm seeing "weird" behaviour.
I can run mosquitto itself and it starts listening. Running either of the clients mosquitto_pub or mosquitto_sub fails, they appear to hang, and the broker never receives any connection. I also cannot use them to connect to any other broker, local or otherwise.
I can send messages from e.g. Python or Java client apps to the running broker.
Compiling with WITH_SRV=no appears to have no effect on the behaviour of the client apps, and running with debug enabled doesn't have an effect either. I've tried running a trivial C app against libcares and it works, so I'm guessing the issue is not that, but that just happens to be a new dependency.
Obviously I don't want to push a homebrew formula upstream until I know this will work...
