There is an updated pull request by skmpz against master on the void-packages repository

https://github.com/skmpz/void-packages calibre-5.6.0
https://github.com/void-linux/void-packages/pull/26761

calibre: update to 5.6.0.


A patch file from https://github.com/void-linux/void-packages/pull/26761.patch is attached