Cannot launch Xamarin.iOS app on device

Question

I am developing an iPad application with Xamarin.iOS and MVVMcross. So I have a PCL with my View-Model and my Model, and an iOS project with the view. I use Visual Studio.

Before, I used Xamarin.iOS 6.3.6 beta version, and when I tried to launch the app on the device, an .app file was created and getting it with my Ipad, I could launch the application (impossible to launch directly from Visual Studio).

Yesterday, I uploaded Xamarin.iOS to 6.4.1. On simulator, everything's okay. When I try to launch the application on device, now the app is directly installed but the build stop and the following error appear in the debug output :

Failed to load AOT module '<my PCL>' while running in aot-only mode: doesn't match assembly. 

And if I click on my app icon on the device,a black screen appear and disappear immediately.

Does someone know why this error appear?