For ease of testing there are now some binaries available for testing the upcoming 2.1 release. We would strongly urge everyone using mosquitto to test out these versions and provide feedback if anything doesn't work as you expect.
The version in these binaries is listed as 2.0.99.
There are currently three options available:
Snap
For the x86_64 architecture only.
Update to the edge channel to get the test:
snap refresh --channel=edge mosquitto
Revert to normal using:
snap refresh --channel=stable mosquitto
Windows
Download the 64-bit installer
Docker
The mosquitto docker images are provided the the Official Images program by Docker, it would not be appropriate to put test images there. Given the restrictions Docker Hub places on pull images we are also looking at alternatives. Until the 2.1 release is made, testing images will be available hosted by Cedalo. Cedalo provide a paid version of mosquitto with enterprise features.
Note that the images are produced in a slightly different way to the normal images, so there is some wasted space. This is not representative of the final images.
docker pull registry.cedalo.com/eclipse-mosquitto-2.1-testing/mosquitto:latest
Other
We would like to provide Debian packages, but they are still in progress and we didn't want to delay the other binaries.