NSDateFormatter and current language in iOS11

Question

It appears that default behavior for NSDateFormatter has been changed in iOS11. This code used to work and produced date formatter according to currently select

Answer 1

Yes, the default behaviour is changed in iOS11 exactly as @rmaddy described.

In my case, I have a project with a base development language set to English but, on iOS11, when I changed the device's language to any other language (say Swedish) the dates would still be displayed as, for instance, Monday 6 November. This happened because my app didn't support any localization.

The solution was simple: in order to have the app displaying the dates in Swedish I just had to add an empty Strings.strings file and then, in projects settings, I added the Swedish localization. Although the strings file is empty, the app then became localized in Swedish so by changing the language, in Settings, to Swedish, we could see the same date as måndag 6 november, thus achieving the desired use-case of iOS10.

Note: if you do something like this and it doesn't work for you, when adding a language in Project Settings make sure to go to "Other" and pick a language from there (instead of just choosing one from the first-level dropdown).