A Community Technology Preview (CTP) is a version of a Microsoft product that is released to early users and software developers for testing before the start of general availability. Microsoft began using the CTP process in 2004 to get user feedback and bug reports on new software releases that were under development. The Community Technology Preview has become a key part of the software release lifecycle for Microsoft products and is similar to a beta test release.
Microsoft typically issues a series of Community Technology Preview releases on a particular product, often starting with a private release to a limited group of users before moving on to public previews that are openly available for download. Development teams at the software vendor group plan features into different CTP releases, usually adding new functionality and updating existing elements in each one. This approach is intended to enable Microsoft's developers to balance the delivery of new features with enhancements and fixes to features from previous releases based on feedback from users.
As an example, there were 10 Community Technology Preview releases for Microsoft's SQL Server 2016 database: an initial private one followed by nine public previews issued between May 2015 and February 2016. As part of that process, the SQL Server development team also adopted what it described as a "rapid preview model" borrowed from the Microsoft Azure cloud platform. That resulted in more frequent CTP updates than was commonly the case in the past, when new versions might be released every few months. In addition, early SQL Server 2016 users weren't required to upgrade to the most recent CTP release if they preferred to continue with the one they were already running.
While a Community Technology Preview is primarily intended for development and test uses, it can also be used in a limited production environment, although such deployments wouldn't be covered by Microsoft support. In the company's development lifecycle, the CTPs are generally followed by multiple "release candidate" versions before a product becomes generally available. The release candidates are almost feature-complete, but provide bug fixes and further enhancements for final testing.