This is a new features release. It offers quite a bit of change over the previous version. More details of the new features can be found in the [man pages]. The substantial changes are: * Basic support for connecting multiple MQTT brokers together (bridging). * mosquitto_sub can now subscribe to multiple topics (limited to a global QoS). * mosquitto_pub can now send a file as a message. * mosquitto_pub can now read all of stdin and send it as a message. * mosquitto_pub can now read stdin and send each line as a message. * Implement a more efficient database design, so that only one copy of each message is held in the database, rather than one per subscribed client. * Add support for automatic upgrading of the mosquitto DB from v1 to v2. * If a retained message is received with a zero length payload, the retained message for that topic is deleted. * Implement the `max_inflight_messages` and `max_queued_messages` features in the broker. The less visible features and bug fixes are as follows: * Add support for disabling `clean session` for the sub client. * mosquitto will now correctly run VACUUM on the persistent database on exit. * Add the `store_cleanup_interval` config option for dealing with the internal message store. * Add `persistence_file` config option to allow changing the filename of the persistence database. This allows multiple mosquitto DBs to be stored in the same location whilst keeping `persistence_location` compatible with rsmb. * Don't store QoS=0 messages for disconnected clients. Fixes bug #572608. This wasn't correctly fixed in version 0.5. * Don't disconnect clients if they send a PUBLISH with zero length payload (bug #573610). * Send through zero length messages. * Produce a warning on unsupported rsmb options instead of quitting. * Describe clean session flag in the mqtt man page. Get it from the [download page]. Windows and Ubuntu binaries will follow along shortly. [man pages]: /documentation [download page]: /download