TLDR: SmallRye Reactive Messaging 2.x is not under development anymore. If you still use it, switch to 3.x.
SmallRye Reactive Messaging 2.x was first released in April 2020. That version was used in Quarkus 1.x. However, no release has been required since March 2021. Indeed, we started working on the 3.x version of SmallRye reactive messaging, and Quarkus 2.x uses that version, as well as Wildfly. SmallRye Reactive Messaging 2.x was integrated with Vert.x 3.x and MicroPRofile 3.0. Both have been replaced with more recent versions.
As a result, it's time for us to stop maintaining this branch and work on future developments and innovations.