title: Android gradle: what do square brackets around the version mean?
body: <p>In Facebook Android sdk's get started guides, they define two ways to add the dependency to your project.  In the Getting Started section, the line in gradle is </p>
  
  <pre><code>compile 'com.facebook.android:facebook-android-sdk:4.+'
  </code></pre>
  
  <p>but in the Quick Start guide, the line is </p>
  
  <pre><code>compile 'com.facebook.android:facebook-android-sdk:[4,5)'
  </code></pre>
  
  <p>Additionally, Android Studio warns that you shouldn't use '+' in version numbers, leading to unrepeatable builds.  I have seen the '+' for other dependencies and I believe it means to get the latest version when you sync gradle, but what do the square bracket and parentheses mean in the second line?  </p>