Plex requires systemd now

I’ve been running Plex Media Server for several years on a
box running PCLinuxOS, which does not use systemd.
I’m currently on version 1.14.1. Today I tried to upgrade to
1.15.2, and I got this error:

Plex Media Server requires systemd. Please upgrade the Operating Systm (sic) version (Note: the message misspells System, that’s not my typo)

Is there a technical reason Plex is now requiring systemd?