title: App crashes after AppStore upgrade
body: <p>I have just release a new version of my app to Apple which Apple approved. The version works great... for new users. But for "old" users the app crashes. They have to uninstall the app and then re-install it.</p>
  
  <p>I have some users still running 3.1.3 which even see app crashes after unstalling and re-installing it.</p>
  
  <p>This is the crash log from one of my users:</p>
  
  <blockquote>
    <p>Date/Time:       2010-11-25 17:29:00.476 +0100<br/>
    OS Version:      iPhone OS 3.1.3 (7E18) <br/>
    Report Version:  104<br/>
    <br/>
    Exception Type:  EXC_BREAKPOINT<br/>
    (SIGTRAP) Exception Codes: 0x00000001,<br/>
    0xe7ffdefe Crashed Thread:  0<br/>
    <br/>
    Dyld Error Message:   Symbol not found: __NSConcreteGlobalBlock<br>
    Referenced from:<br/>
    /var/mobile/Applications/2B003960-53A3-479A-9132-FE38C4AE88A2/stationen.app/stationen<br/>
    Expected in:<br/>
    /usr/lib/libSystem.B.dylib  in
    /var/mobile/Applications/2B003960-53A3-479A-9132-FE38C4AE88A2/stationen.app/stationen<br/>
    Dyld Version: 149<br/></p>
  </blockquote>
  
  <p>This doesn't say me anything, can anybody help me with it?
  App works great on my iPhone 4 running 4.1.</p>
  
  <p>Regards,<br/>
  Paul Peelen</p>