Back in 2020 we added MQTT support to curl.
When curl 8.19.0 ships in the beginning of March 2026, we have also added MQTTS; meaning MQTT done securely over TLS.
This bumps the number of supported transfer protocols to 29 not too long after the project turned 29 years old.
What’s MQTT?
Wikipedia describes it as a lightweight, publish–subscribe, machine-to-machine network protocol for message queue/message queuing service. It is designed for connections with remote locations that have devices with resource constraints or limited network bandwidth, such as in the Internet of things (IoT). It must run over a transport protocol that provides ordered, lossless, bi-directional connections—typically, TCP/IP.
Coming protocol support reduction
If things go as planned, the number of supported protocols will decrease soon as we have RTMP scheduled for removal later in the spring of 2026.
Is the date of May 2026 actually correct ? This seems far away compared to the release schedule of curl, especially considering that the PR implementing it is already merged.
@Christophe: oh right, thanks. It should be beginning of March 2026, no other month. Fixed now.