This e-reader is quite dumb and only talks to the world via propietary GUI app so I don't think it had a friendship with a selfhosted Calibre. There is a hacked python module to pilot the e-reader but some extra glue would be needed. In my case my data model is laptop first and then have backups on other places including NAS, after, so I prefer to have Calibre in laptop. I can map a NAS path to a laptop folder and Calibre sees it as a device, with a nice send-to-device button. So I just need to end the glue to sync the e-reader with the NAS. Calibre automatically converts EPUBs to pdfs. Having bought a Kindle DX back then, I can even setup a Calibre DRM plugin with the Kindle serial number, buy an e-book in Amazon, click on the AZW file, and have a PDF generated automatically :-) For papers, I prefer to manage them separately.