I found that I get a different value about current locale from NSLocale between iOS 11 and iOS 10.
NSLocale.current.languageCode
When I set device language to Japanese and English at setting application, I get "en" at iOS 11 "ja" at iOS 10.
But after I add Japanese string files to my application (a.k.a Localizations), I get "ja" at iOS 11.
This behavior is mentioned at StackOverflow, but are there any official references?
https://stackoverflow.com/a/46206511/4834226
> Under iOS 10 and earlier,
currentLocale
would directly represent the user's chosen language and region, regardless of what localizations your app supports.> iOS 11 fixes this inconsistency. While one could argue that this change breaks lots of apps that only support one (or just a few) language, it actually makes the app more consistent.