Perhaps not many people have had two Apple IDs each tied to a different country’s App Store / iTunes Store. I have, for various reasons. On my iPhone, the majority of the apps installed were purchased from my main Apple ID (ending in @mac.com), tied to the Spanish App Store; but I also have another Apple ID tied to the Italian App Store. 

iOS has always handled this ‘double identity’ in an atrocious, counter-intuitive way. Suppose you have App 1 and App 2 purchased from the Spanish App Store, and App 3 purchased from the Italian App Store. One day, updates to App 1, App 2 and App 3 become available. The ‘App Store’ app shows all three updates. You tap on the ‘Update all’ button.

Up to now, what used to happen was this:

1. iOS asked for your first Apple ID’s password.
2. App 1 and App 2 started downloading and then got installed.
3. The update for the App 3 remained there, forcing you to open the App Store app again and tap to ‘Update’ again.
4. iOS asked for your second Apple ID’s password.
5. Instead of starting the download of App 3, iOS displayed a warning like This account is only valid for purchases in the Italian iTunes Store (I’m quoting from memory).
6. You tapped OK. Then the iTunes app would open.
7. You quit the iTunes app and noticed App 3 download was in progress and that App 3 was finally installing.

I honestly can’t tell whether this change happened in iOS 5, 5.0.1 or 5.1 but now, finally, iOS handles all this process in the logical way: when you have mixed updates pending from two different Apple IDs / App Stores, you are asked both passwords and all the apps are downloaded and installed in a single pass.