Update 12 Oct 2019: The aptalca calibre image no longer works due to incompatibility with Calibre 4+
I just got a used Synology DS411+II which is an intel-based NAS.
I copied my existing Calibre library from my PC to my NAS, and then install Docker and aptalca docker-rdp-calibre:
https://github.com/aptalca/docker-rdp-calibre
First time playing with Docker and after several hours of trying, I am glad I can get it running, both the Calibre full package and Calibre content server.
Calibre will automatically restart when my NAS restart (Docker will automatically restart too).
I've tried succesfully the schedule news download, email. Will further explore.