Starting with Xcode 4.5 the possibility of building for armv6 devices is not given anymore (iPhone/iPod touch 1st and 2nd generation). This means no new versions of our app for
You can have multiple versions of xcode installed. In the past, that has been the fix needing to use an older xcode feature.
It is a workaround, and the project files may eventually evolve in a way that no longer supports the older tools, but for the time being, that will allow you to build for older targets.
If you have a single project that you want to work with in both versions of XCode, then you may end up having to manage separate project control files via source control tricks and/or file shuffling.
I would also recommend that project structure changes and binary file management (e.g. Core Data models) happen via the old version, as XCode 4.5 will be backward compatible, but forward compat is rarely assured.