calibre-server converts PDF on "Read" on Pi 4

[tanmaychhatbar]

I'm hosting on a headless server on RPi4. When I use the Calibre website 192.168.x.x:8080 and "Read" an EPUB, the experience is perfect.

But, when I "Read" a PDF, it says, "Book is being prepared on the server" for a few seconds before displaying a text version of the book, i.e., as I understand it, converts from PDF to EPUB.

When I host a server on my Windows laptop, the "Read" button opens the PDF in a new tab, which is the desired behavior. How do I replicate this behavior on the server hosted by Pi?

I've tried looking for a solution online and reading some source code. Since the servers on Windows and Linux show different behavior, and I have practically no experience in debugging something like this, I'd like some help. Thanks

[kovidgoyal]

Update the version of calibre on your Pi

[tanmaychhatbar]

Update the version of calibre on your Pi

Solved. It was a version issue. Thank you!

I had assumed apt upgrade would keep Calibre updated. That is not the case. I was on Calibre 5.1!
I tried installing 7.4, but it mentioned how 7.4 requires GNU libc v2.34, while the distro I'm using is on v2.31.

Found this thread where Kovid mentioned one could update up to v6.7.0. I verified that v6.7.0 can be installed, v6.8.0 shows the same error as above.
https://www.mobileread.com/forums/sh...d.php?t=350896

Once Calibre was updated (as far as it could have been), requests to "Read" exhibit the desired behavior of opening a PDF in a new tab.