title: Differences between CTP, Alpha, Beta, Gamma, RTM and Preview for Software Release?
body: <p>It is quite intuitive that at least Gamma comes after Beta and Alpha.</p>
  
  <p>But how about CTP, RTM and Preview releases? Which one comes first and last?</p>
  
  <p>MEF (Managed Extensibility Framework) is currently on <a href="http://mef.codeplex.com/Release/ProjectReleases.aspx?ReleaseId=25797" rel="noreferrer">Preview 5</a> release, but I am not sure if it is a release before Alpha or after Beta, CTP or RTM.  Is it OK to use preview releases in production code?</p>
  
  <p>What are the differences between those releases?
  I am particularly interested in knowing differences between </p>
  
  <ul>
  <li>RTM</li>
  <li>CTP</li>
  <li>Beta </li>
  <li>RC</li>
  <li>Preview</li>
  </ul>
  
  <p>releases.</p>
  
  <p>It seems like everywhere each releases mean different things.</p>