Translation files update
If you update the theme you will also need to update theme translation to keep it up to date and avoid problems with untranslated strings.
Update translation using poEdit
Open .po file and press Catalog > Update from POT file
Choose the pot file that is located in xstore/languages/ folder on your site.
Save changes and re-upload translation files to your site.
Update translation using Loco Translate plugin
Edit translation and press the Sync button
Save translation.