Translation files can be reloaded without upgrading the addon modules by repeating the Load a Translation action. This can be used in case you have updated translation files and don't want to go through the trouble of upgrading the modules (and all their dependencies).

If the Overwrite Existing Terms checkbox is left empty, only newly translated strings are loaded. Thus, changed translated strings won't be loaded. Check the box if you want the already existing translations to also be loaded and overwrite the currently loaded translations. Note that this can be potentially disastrous if someone changed translations manually via the interface.

The previous checkbox exists because we can do our specific translations editing Settings | Translations | Application Terms | Translated Terms, or using the Technical Translation shortcut option in the Debug menu. Translations added or modified this way won't be overwritten unless the language is reloaded with the Overwrite Existing Terms checkbox enabled.

It can be useful to know that addon modules can also have an i18n_extra subdirectory with extra translations. The loading sequence for the translation files is the .po files in the i18n subdirectory, first for the base language and then for the language; after that, the .po files in the i18n_extra subdirectory, first for the base language and then for the language. The last string translation loaded is the one that prevails.