legacy ios devices, running ios 6 new resolution

No, you just will not upgrade to the newer apps

 

No, they will work just like how they are now. Apps updated for 5 will look normal in 5 and normal in your device.

Not true. Newer apps will just need to be updated for 5 and it will run on both devices.

 

Typically, the developer has to put some effort into making sure his app sizes appropriately.

If you run a pre-iPhone5 app on an iPhone 5, it gets letterboxed or pillarboxed (depending on orientation).

What happens when you run an app made by a lazy developer for iPhone 5 only, on an iPhone 4S or earlier, no one knows. We'll find out as soon as the thing is available.

 

It's not any different when we went from 3G/3GS to 4. Apps worked on both devices, but updated to work in retina as well. Same with 5.

Not all apps. Apps have to be updated by the developer. If they're not updated, it will be letterboxed (black line above and below app) on the iPhone 5.

 

there are diff versions to run on each device inside the app itself..the ios version loads the graphics right for your screen

 

the way it works is a developer creates multiple UIs for different resolutions...this is already done by apps that are universal for iPhone and iPad.

In theory, a developer could choose to support ONLY the iPhone 5, but if they don't make a UI for 3.5" screens, Apple won't allow it to be marked to run on older devices. They'll tell the developer to make a UI if they want their app available on older devices. So the app wouldn't be available to nearly as many people, and no developer is dumb enough to do that. Especially when porting the app to the different resolution takes very little time (I'd estimate most apps could make the shift in < 10 hours)

 

This is correct. The app checks which device it is running on before loading and then loads the proper images, buttons, etc. Kind of like a universal app. Its the same downloaded software and when it's run, the appropriate UI is loaded.