PostgreSQL beta releases are pre-release testing versions, not meant for production use. They are feature-frozen, and we release these to the public for testing before our final release.
Beta versions should not be used in production installations or active development projects. While the PostgreSQL code is continuously subject to a number of automated and manual tests, beta releases might have serious bugs. Also features may be changed incompatibly or removed at any time during the development of the betas.
The development cycle of a PostgreSQL major release alternates between periods of development and periods of integration work, called commit fests, normally one month each. As we approach release, we will release a series of betas, as needed.
The current beta is 9.3 Beta 1.
Betas are meant for everyone who uses PostgreSQL to test before we release the final version. There may still be serious bugs, so these versions are not meant for production use.
We depend on our large community of users to test the features in beta releases and report issues. If you are able to contribute to PostgreSQL by doing beta testing, please see our Alpha/Beta Testing Page.