title: Reliable server-to-iPhone messaging
body: <p>My company offers an iPhone app for day traders which basically tells them when it's a good time to buy or sell. A cluster of servers generate these BUY and SELL signals and need to be delivered to a customer's iOS device in a minute or less. For all other mobile clients we've developed, we are allowed to poll the server in the background (once per minute), to check for updates.</p>
  
  <p>In iOS, however, it seems that doing anything in applicationDidEnterBackground that has to do with times or polling isn't an option.</p>
  
  <p>This led me to look at push notifications, but from what I am reading, they aren't reliable. They employ a send-and-forget methodology, which there's no guarantee they will be received. </p>
  
  <p>You can see the problem with this. If we issue a BUY signal and the user acts on it, then a SELL signal is generated 10 minutes later and send via push, but never arrives, they could lose a lot of money.</p>
  
  <p>So, is there a good way to do this or am I out of luck? Thanks!</p>