Check the package source to make sure there are .mo and .po files.
Language_Pack_Upgrader::bulk_upgrade
Bulk upgrade language packs.
Language_Pack_Upgrader::upgrade_strings
Initialize the upgrade strings.
Language_Pack_Upgrader::upgrade
Upgrade a language pack.
Advertisement
Language_Pack_Upgrader::async_upgrade
Asynchronously upgrades language packs after other upgrades have been made.
async_update_translation
Filters whether to asynchronously update translation for core, a plugin, or a theme.
Language_Pack_Upgrader
Core class used for updating/installing language packs (translations) for plugins, themes, and core.