The deployment target of MailCore and its submodules are unset, leaving it to Xcode to set based on the latest available SDK bundled with it.
The result is that when compiling a project with Xcode 4.5, the deployment target of MailCore and its submodules default to iOS 6.0.
This means that apps compiled with Xcode 4.5 will crash when running under iOS 5 or earlier, even though MailCore supports iOS 5 or earlier.
The workaround is to manually go through the Build Settings of MailCore and its associated submodules, and changing the iOS Deployment Target to 5.0 (or earlier).
Perhaps MailCore should consider setting the deployment target to its minimum supported OS.
I confirm this. I've had to change the deplyment target as well to 5.1
Is this the problem when a dynamic library fails to load?
just got the same problem, junjie gives right solution, but does mronge hear us?
Same problem here. Problem is I can't push this setting to version control because it's done in MailCore itself.