It's pretty straightforward though, and reads as follows:
The PostgreSQL project aims to fully support a major release for five years.
After a release falls out of full support, we may (at our committer's discretion) continue to apply further critical fixes to the source code, on a best-effort basis. No formal releases or binary packages will be produced by the project, but the updated source code will be available from our source code control system.
This policy will be followed on a best-effort basis. In extreme cases it may not be possible to support a release for the planned lifetime; for example if a serious bug is found that cannot be resolved in a given major version without significant risk to the stability of the code or loss of application compatibility. In such cases, early retirement of a major version may be required.
|PostgreSQL 7.4||July 2010 (extended)|
|PostgreSQL 8.0||July 2010 (extended)|
|PostgreSQL 8.1||November 2010|
|PostgreSQL 8.2||December 2011|
|PostgreSQL 8.3||February 2013|
|PostgreSQL 8.4||July 2014|