Steps:
Added “German” localization as a secondary language.
Added all the localized text under "Prepare for submission".
Added all the localized screenshots for
iphone 6,5"
iPhone 5,5"
ipad 12,9" 3rd Gen
ipad 12,9" 2nd Gen
Selected "App Information" (under "General").
Chose "German" in the dropdown-list "Primary Language" and saved.
What happened:
An error-message was displayed:
You have one or more errors on this page.
Possible problem:
Under the "Media Manager" in the context of my app, in the section "iMessage App" as well as "Apple Watch", it claims that it uses references of "English (U.S.)" screenshots.
However, the app supports neither "iMesage App" nor "Apple Watch", and when I switch to "English (U.S.)"-localization, there are neither screenshots nor references under "iMessage App" and "Apple Watch".
My App neither supports "iMessage App" nor "Apple Watch", and the English localization doesn't appear to require dedicated screenshots (or references to screenshots) for these options.
This problem seems to have been already answered here:
https://stackoverflow.com/a/39884724/6607940
However the solution doesn’t work since "Use XX_LANGUAGE_XX Apple Watch” doesn't appear to be checkable/ selectable (anymore?) in the context of the Media Manager.
The apple support has posted an answer I want to share with anyone who struggles with this problem like I did:
Turns out that in order to change the primary language to German (or any other alternative language, for that matter) you need to submit the app with German as an alternative language, adding all the texts and the required localized screenshots.
Once the update is approved you should be able to change the default language from English to German in the context a subsequent app-submission.
For details please see the reply