title: iOS SDK Detect if app was updated or a new install
body: <p>After looking at a bunch of SO posts about detecting if this is a fresh install or not, I'm assuming what I want to do is impossible, but I'm going to ask just in case there's a trick I'm unsure of.</p>
  
  <p>I am building an SDK to be integrated into apps, and I want to be able to tell when the SDK gets initialized for the <strong>very first time</strong> if it's from a brand new install, or from an app update which included our SDK.</p>
  
  <p>I could have the integrator to call something like <code>[MySDK initializeIsNewInstall:YES/NO]</code> and force them to figure out which it is (using NSDefaults or whatever), but I'd rather be able to figure it out automatically somehow. </p>
  
  <p>If anyone has any ideas, that would be great.</p>