Today saw the release of PostgreSQL 9.5 Alpha 1. Packages for all supported Debian and Ubuntu releases are available on apt.postgresql.org:
deb http://apt.postgresql.org/pub/repos/apt/ YOUR_RELEASE_HERE-pgdg main 9.5
The package is also waiting in NEW to be accepted for Debian experimental.
Being curious which PostgreSQL releases have been in use over time, I pulled some graphics from Debian's popularity contest data:
Before we included the PostgreSQL major version in the package name, "postgresql" contained the server, so that line represents the installation count of the pre-7.4 releases at the left end of the graph.
Interestingly, 7.4 reached its installation peak well past 8.1's. Has anyone an idea why that happened?