This release brings the new MQTT v3.1 features to the broker - client authentication and topic access control. See [mosquitto.conf(5)] or the included example password and ACL files. * Implement support for the `password_file` option and accompanying authentication requirements in the broker. * Implement topic Access Control Lists. * `mosquitto_will_set()` and `mosquitto_publish()` now return `MOSQ_ERR_PAYLOAD_SIZE` if the payload is too large (>268,435,455 bytes). * Bridge support can now be disabled at compile time. * Group together network writes for outgoing packets - don't send single byte writes! * Add support for `clientid_prefixes` variable. * Add support for the `clientid` config variable for controlling bridge client ids. * Remove 32-bit database ID support because htobe64() no longer used. * Multiple client subscriptions to the same topic result in only a single subscription. Bug #744077. Please see the [download page]. Thanks to Adam Rudd, Joshua Lock,  Sang Kyeong Nam and Yuvraaj Kelkar. [mosquitto.conf(5)]: /man/mosquitto-conf-5.html [download page]: /download