The Localization update module not only allows you to import contributed translations, but also to fetch and apply translation updates when they become available.

By default, you have to check for updates manually. This can be changed by going to the translation updates tab found at the toolbar, Configuration, Languages. The configuration page also allows you to determine how locally changed translations should be treated – either keeping them on new updates (default), or overwriting them if their remote translations have changed.

You may check for translations updates manually by visiting the update tab in the toolbar, Configuration, Translate interface.