Sony Xperia Z1 compact w/ Android 5.1.1: how to change locale setting? A few days ago I realized that something / someone partially changed localization settings on my (non-rooted) Xperia Z1c. Default language and locale is German / Germany ("de"), and to the day numbers, times and mostly dates are in correct format - with one exception, the simple date format: if all was fine today would be "07.10.2015" (DD.MM.YYYY), but on my device it's showing as "10.07.2015" (MM.DD.YYYY); it's a bit like US locale but with dots instead of slashes as delimiters. And only for simple dates: other date formats are showing alright (07. Oktober 2015, 07. Okt.). As far as I can tell right now this applies to all apps (custom and system default) that are using this date format (e.g. WhatsApp, Evernote, WetterOnline as well as system pages like list of downloaded apps and many more).

I don't have a clue what or who made those changes (maybe unknowingly I did it myself?), nor do I really know when this happened; only thing I know is that the last system update (5.0.2 >> 5.1.1) was pushed from Sony sometime early September, and I think (but I'm far from sure) that before that everything was fine. On the other hand, I also own an Xperia Tablet Z as well running 5.1.1, but NOT having that problem.

I searched every page in system settings but there's no trace of an option to change locales. I can switch languages but that doesn't change locales.

Is there probably some very well hidden setting allowing me to switch locales back to standard? Will I really have to factory reset my device then reinstall everything, and would that even help? Would it probably help to root the device?
Finally I got an answer from Sony's helpdesk: only solution is to reset then re-install the device :( And so I did, and - although this took me quite a bit of time - at least everything behaves as before; too stupid Sony doesn't allow to alter localization settings as others do (like Samsung, HTC, and even plain Android...)