In App Store Connect, which is the default version information displayed on the App Store for the text fields "What's new in this version" & "Promotional Text" in the localized alternatives?
Is the following assumption correct?
The version information is provided in English in the App's main language "English US" and in Spanish "Spanish (Spain)":
Or are both text fields being left empty actually don't display anything in the App Store?
I feel like having to copy&paste the English version manually for all localised versions (using only localised keywords) shouldn't be necessary.
If you have tested this or seen the actual behaviour, I'd very much appreciate your answer.
Answer from Anand is not correct.
1) For all required fields (like description, keywords, what's new etc.) you must insert something for all active languages/localizations over at App Store Connect.
Example: If you start version 1.0 with English (en-US) as your primary locale and add Spanish (es-ES) to your version 1.1 you must insert something in the "What's new" section for Spanish. (As for all other required fields) Otherwise App Store Connect won't let you submit the app for review.
App Store Connect won't validate or check your translations, so you could translate your general metadata once and "keep" the "What's new" section English, but you must copy & paste the information.
2) Optional fields (promotional text, marketing URL etc.) can be left blank or only filled in for one language, but the App Store will not mix and match locales.
Example: If you insert a promotional text for English (en-US), which is your primary locale, and none for Spanish (es-ES), the Spanish localization will not display any promotional text.
With regards to when which language is used, check out this paragraph from the App Store Connect Help:
For example, if the primary language you select for your app in App Store Connect is English and it’s the only language you provide, your app metadata in all App Store territories appears in English. If you localize your app metadata in French, users whose language setting is French will see the French localization. Users in territories where the App Store supports French but not English also see the French localization. Users can search for your app using localized keywords in all territories where the App Store supports French. If there’s no localization available that matches the language setting, the next most relevant localization is used. In other App Store territories, users see your metadata in the primary language (English in this example).