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* Upgrade BWIPP from 2015-11-24 to 2017-06-20. This has a number of bug fixes,
and supports more barcode types. It has also changed the pixel-for-pixel
output of some formats, although they still encode the same information -
notably QR codes, which are tested in ``treepoem``\'s test suite. You can
read its changelog in the `vendored copy in the treepoem repo
<https://github.com/adamchainz/treepoem/blob/main/treepoem/postscriptbarcode/CHANGES>`__.