Hello Andreas, I have briefly did diff between Babel 2.3.4 and 2.4 and found one suspicious change which would generate such error: - https://github.com/python-babel/babel/commit/08b9c5e76e19ae610f28759a5cf37621ac2fb734 The change parses "Language: ko-KR\n" line in po files and Korean po files use 'ko-KR', not 'ko_KR' [1]. However, the change just call Locale.parse() function without considering '-' character, and Locale.parse() function assumes that '_' is the separator if not specified [2]. I think it would be one possible candidate which caused such error. With many thanks, /Ian [1] http://git.openstack.org/cgit/openstack/openstack-manuals/tree/doc/install-guide/source/locale/ko_KR/LC_MESSAGES/install-guide.po#n42 [2] https://github.com/python-babel/babel/blob/v2.4.0/babel/core.py#L221 Andreas Jaeger wrote on 4/5/2017 7:05 PM: > I see in: > http://logs.openstack.org/8d/8d993d3bbd17ce22288b9ea9caa6d93618522f46/post/openstack-manuals-tox-doc-publishlang/53125a3/console.html#_2017-04-05_07_35_50_515860 > > "ValueError: expected only letters, got u'ko-kr'" > > Is there anybody that can investigate whether Babel is broken and needs > blacklisting - or what else needs to change? > > This is using BAbel 2.4.0, > > Thanks for any help, > Andreas