title: Android differences between signed and unsigned .apk files?
body: <p>How many difference between signed and unsigned .apk files in android?</p>
  
  <p>I know only one when i integrate in-app purchase i have unsigned .apk its gives me error 
  <code>Item version is not same as...</code> </p>
  
  <p>and also we cant install unsigned .apk file in android device...</p>
  
  <p>is there any other Diffrences ?</p>