Snort version 2.9.15.0 has officially reached its end of life. Version 2.16.0 remains active, as there are still external commitments. Users are encouraged to update to a more recent version of Snort as soon as possible if they are still using the old version. Older Snort rule integrators are using very old versions (2.8.3 for example), which is the reason those versions are still around. We are actively working with these partners to move them to more current versions.”]
Source: https://blog.snort.org/2021/07/29150-has-reached-its-end-of-life.html