Hi @TruePepe,
Did you update the locale setting in the i18n section of config.inc.php to the new two-letter style of code?
What do you have for the installed_locales and supported_locales columns in the site table?
What do you see in the primary_locale column of the journals table?
What do you get for the following query?
select * from journal_settings where setting_name in ('supportedFormLocales', 'supportedLocales', 'supportedSubmissionLocales');
And finally, have you tried flushing your data cache? (You can do this in the administrator’s interface, or manually by removing all .php files from cache/ and all files from cache/opcache. If your file permissions in cache/ are not set properly, the administrator interface cache clear may not work fully.)
Regards,
Alec Smecher
Public Knowledge Project Team