Differences between CTP, Alpha, Beta, Gamma, RTM and Preview for Software Release?

It is quite intuitive that at least Gamma comes after Beta and Alpha.

But how about CTP, RTM and Preview releases? Which one comes first and last?

MEF (Managed Extensibility Framework) is currently on Preview 5 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?

What are the differences between those releases? I am particularly interested in knowing differences between

• RTM
• CTP
• Beta
• RC
• Preview

releases.

It seems like everywhere each releases mean different things.

From stackoverflow

• The answer is "It depends".

  All of these badges mean different things for different people, and things like "CTP" and "Preview" even more so.

  Where relevant (e.g. frameworks) most preview/beta/ctp releases will come with information about whether they should be used in shipping code or not. Generally if they require an end-used redistributable the answer is no.

  Sung Meister : So does that mean, using a Preview release software like MEF probably is not a good idea in a production code?

  : Don't use it in production code!

• The stages are typically Alpha, Beta (can be broken into Internal vs. External), Release Candidate (RC), Release to Manufacturing (RTM). "Community Technology Preview" (CTP) or just plain "Preview" are, in my opinion, merely euphemisms for Beta (which implies "contains plenty of bugs").

• It can very by company to company. They are usually defined like this:

  • CTP - Community Technology Preview - Not beta quality, not as wide-spread. Not necessarily feature-complete. Usually intended for partners who will build on top of the product.
  • Preview - Usually like a CTP.
  • Beta - Widespread release. Expected to be mostly stable, feature complete.
  • RTM - Release to manufacturing. Final release of the product, the "Gold" release.

  As for using previews in production code, it depends again, but is usually a bad idea. They are usually not that well supported.

  Sung Meister : I am still not able to grasp the difference between CTP and Preview. But from the description at least RTM comes later than Beta does.

• I've most commonly seen those terms used in the following ways

  • CTP (Community Technology Preview): Very much like "Show and Tell". Features are present to varying degrees and customer can get an idea of where the release is going
  • Beta: Features are mostly implemented but still have rough edges. Quality is fair at this point. The higher number beta, the higher the quality
  • RC (Release Candidate): Product believes it's ready to ship. One last chance for customers to provide feedback and find major blocking issues
  • RTM (Release to Manufacturing): Product is complete and ready to be shipped to customers