OpenSIPS release policy is designed in such a way to be open (everyone is involved), predictable and reliable (know what to expect) and transparent (to the whole community).
From maintenances point of, there are two types of releases.
The only difference is just for how long they are supported. The releasing process, stability and everything else is the same for all.
This model aims to maintain a decent balance between getting features out the door and supporting the existing release. People wanting new features can go for the standard releases, and those looking for stability and better support can stick with the long term support releases.
By supporting a version, we understand troubleshooting, fixing bugs, and backporting various new fixes from more recent OpenSIPS versions. Also, we will take care maintaining packages and tarballs for the supported releases.
Once an OpenSIPS release moves to unsupported status, it will not get any new bug fixes, any packaging or new tarballs.