“The ‘old’ Particle Hair System will still be available, but is no longer being developed.“
How do you know that it is no longer being developed please? Will they completely discard the ‘old’ Particle Hair System in the future please? I thought that geometric nodes were unable to completely replace the ‘old’ Particle Hair System.
I also remember that once upon time, Blender Game Engine was a thing until they completely discarded it in 2018.