Support matrix: luberjack plugin

Dear elasic colleagues,
what I do not understand:
You provide a support matrix for the logstash plugins

In this matrix I do not find the lumberjack output plugin.
This means for me: this plugin is not supported anymore.
But on the other side if I go to the documentation:

it tells me this:
Plugin version: v3.1.8
Released on: 2021-02-11
So: You do not support this, but you actively develop it? Would you please be so kind and clarify this for me: is it safe / ok to use it (also in terms of support) or not?
Thank you and kind regards
Stefano

Not sure why, it is present in the list of output plugins.