While I agree that going with Arch for a Calibre-only server, just for those guys who are looking for a Raspbian workaround:
https://www.raspberrypi.org/forums/v...9037&p=1086130
This is essentially changing the source list to "testing" and thus installing an newer (but potentially less stable) version than the 2.75 coming with Jessie. 3.4.0
seems in testing now.