After updating the app, user reports crash on iPad 1 running iOS 5.1.1

There is no crashalytics crash report that I get. And the user says that the app just hangs on the opening screen.

And this started happening only a few days ago. Would anyone know why this happens? And is there any reason why this started happening now?

When I run the app on my simulator with iOS 5.1 it works just fine.

Solution

I emailed you the crash logs & console logs. The immediate meat of it looks like you have a problem with ACFacebookAppIDKey...

Dyld Error Message:
  Symbol not found: _ACFacebookAppIdKey
  Referenced from: /var/mobile/Applications/<removed by D80buckeye>/BusinessPlan.app/BusinessPlan
  Expected in: /System/Library/Frameworks/Accounts.framework/Accounts
 in /var/mobile/Applications/<removed by D80buckeye>/BusinessPlan.app/BusinessPlan
  Dyld Version: 199.6

EDIT: With a little more research I think I found your problem. ACFacebookAppIDKey is only available in iOS6 and above. From ACAccountstore Class Reference

ACFacebookAppIdKey
The Facebook App ID, as it appears on the Facebook website.
Available in iOS 6.0 and later.
Declared in ACAccountStore.h.