Hmmm... Looks like this wont just be a simple rebuild.

bumped the version, chanfed 'libusbx' to 'libusb', tried to build and:

 |  ==> ERROR: Could not create a full list of packages, exiting.
 |      This is likely caused by a dependency that could not be found.
 |   > error: target not found: python2-apsw
 |   > error: target not found: python2-css-parser
 |   > error: target not found: python2-html2text
 |   > error: target not found: python2-html5-parser
 |   > error: target not found: python2-mechanize
 |   > error: target not found: python2-netifaces
 |   > error: target not found: python2-pyqt5
 |   > error: target not found: python2-regex

It looks like a lot of the Python2 stuff has gone missing. Since those are [unresolvable] I couldn't use pactree to see their depends. But I'm guessing that they each have a few opf their own that may now be missing.

https://git.archlinux.org/svntogit/community.git/commit/trunk?h=packages/calibre&id=81a9e1b715b5b8601208b299e1d70ab0c96dba88

(Yes, the linked ticket prevents rebuilding calibre3 until the dependencies are re-added to parabola.)

To work around the issue for now:

# pacman -Syu --ignore calibre3 --ignore libusb

I can't recommend the "workaround" posted above. partial upgrades are dangerous and have a real potential to break other stuff.

calibre3 is aging pretty badly, due to its dependencies on python2. Unfortunately, due to newer versions depending on qt-webengine, we can't really bring it up to date without massive time investment. As it stands, we might have to think about dropping calibre alltogether.