The fact that the hex-encoded sortkey must be converted to binary format
for prop=categorymembers cmstartsortkey and cmendsortkey has long been an
odd wart in the API.
Bug 70690[1] showed that the binary values for these parameters is actively
breaking on some wikis. In Gerrit change 159746[2] these parameters have
been deprecated in favor of new parameters cmstarthexsortkey and
cmendhexsortkey which take the sortkey in the same hex-encoded format that
is returned by the API.
This change should be deployed to WMF wikis with 1.24wmf22, see
https://www.mediawiki.org/wiki/MediaWiki_1.24/Roadmap for the schedule.
[1]:
https://bugzilla.wikimedia.org/show_bug.cgi?id=70690
[2]:
https://gerrit.wikimedia.org/r/#/c/159746/
--
Brad Jorsch (Anomie)
Software Engineer
Wikimedia Foundation