You can check if a PO file is valid with the following command:

        msgfmt -c -o /dev/null <po file>
      

The following errors were found in debian-edu-router 's PO files:

gettext: po/it_CARES/LC_MESSAGES/debian-edu-router-config.po: can't guess language
gettext: po/it_CARES/LC_MESSAGES/debian-edu-router-plugin.content-filter.po: can't guess language
gettext: po/it_CARES/LC_MESSAGES/debian-edu-router-plugin.krb5-connector.po: can't guess language
gettext: po/it_CARES/LC_MESSAGES/debian-edu-router-plugin.ldap-connector.po: can't guess language
gettext: po/it_CARES/LC_MESSAGES/debian-edu-router-plugin.mdns-reflector.po: can't guess language
gettext: po/zh_LATN@pinyin/LC_MESSAGES/debian-edu-router-config.po: can't guess language
gettext: po/zh_LATN@pinyin/LC_MESSAGES/debian-edu-router-plugin.content-filter.po: can't guess language
gettext: po/zh_LATN@pinyin/LC_MESSAGES/debian-edu-router-plugin.krb5-connector.po: can't guess language
gettext: po/zh_LATN@pinyin/LC_MESSAGES/debian-edu-router-plugin.ldap-connector.po: can't guess language
gettext: po/zh_LATN@pinyin/LC_MESSAGES/debian-edu-router-plugin.mdns-reflector.po: can't guess language
podebconf: file debian/po/de.po not up-to-date
      

Please ask the translator (identified by the Last-Translator field in the PO file), the language team (identified by the Language-Team field) or debian-i18n for a fix.

There are no up-to-date PO files in your package. You should call for translations before uploading to unstable.

You can send a call for translation using the podebconf-report-po command (package po-debconf):

        cd <po directory>
        podebconf-report-po --call