Last modified: 2014-01-30 23:47:03 UTC
An ISBN with an X at the end is not recognised as an ISBN, see URL for examples.
Parsoid detection of ISBNs is slightly off.
Change 110306 had a related patch set uploaded by Arlolra: Recognize ISBNs that end in an X https://gerrit.wikimedia.org/r/110306
Change 110306 merged by jenkins-bot: Recognize ISBNs that end in an X https://gerrit.wikimedia.org/r/110306