Windows Phone 8.1 update 1 has some stealth new features “not mentioned in official changelog” some of which we could find on our own and reported. As always our Windows Phone 8.1 update 1 page is your best bet to read all that this GDR1 update brings in one place. But there is more to found it seems.
One more unknown feature has revealed itself now. Earlier Office Mobile wasn’t able to open password-protected document. But seems, now it can. Above screenshots demo the before and after Windows Phone 8.1 update 1 scenario. Now, on trying to open protected documents, it prompts for a password. It still only allows to read but not edit such documents.