Security:
- On Windows the Mosquitto service was being installed without appropriate
path quoting, this has been fixed.
Broker:
- Fix usage message only mentioning v3.1.1. Closes #1713.
- Fix broker refusing to start if only websockets listeners were defined.
Closes #1740.
- Change systemd unit files to create /var/log/mosquitto before starting.
Closes #821.
- Don't quit with an error if opening the log file isn't possible.
Closes #821.
- Fix bridge topic remapping when using "" as the topic. Closes #1749.
- Fix messages being queued for disconnected bridges when clean start was
set to true. Closes #1729.
- Fix `autosave_interval` not being triggered by messages being delivered.
Closes #1726.
- Fix websockets clients sometimes not being disconnected promptly.
Closes #1718.
- Fix "slow" file based logging by switching to line based buffering.
Closes #1689. Closes #1741.
- Log protocol error message where appropriate from a bad UNSUBSCRIBE, rather
than the generic "socket error".
- Don't try to start DLT logging if DLT unavailable, to avoid a long delay
when shutting down the broker. Closes #1735.
- Fix potential memory leaks. Closes #1773. Closes #1774.
- Fix clients not receiving messages after a previous client with the same
client ID and positive will delay interval quit. Closes #1752.
- Fix overly broad HAVE_PTHREAD_CANCEL compile guard. Closes #1547.
Client library:
- Improved documentation around connect callback return codes. Close #1730.
- Fix `mosquitto_publish*()` no longer returning `MOSQ_ERR_NO_CONN` when not
connected. Closes #1725.
- `mosquitto_loop_start()` now sets a thread name on Linux, FreeBSD, NetBSD,
and OpenBSD. Closes #1777.
- Fix `mosquitto_loop_stop()` not stopping on Windows. Closes #1748. Closes #117.