From early July until the beginning of this week, the PostgreSQL project has been maintaining eight active branches: 7.4, 8.0, 8.1, 8.2, 8.3, 8.4, 9.0, and the master branch (9.1devel). As a result, a significant number of bug fixes and security updates had to be back-patched into all of those releases. At least for me, the recent switch to git has made back-patching, at least for simple cases, a whole lot simpler. But it's still a fair amount of work - some parts of the code have changed a good deal since 2003, when 7.4 was released.
With the recently announced retirement of 7.4 and 8.0, we're back down to six active branches. When 8.1 is retired later this year (or perhaps early next year), we'll be down to just five. I have mixed feelings about this. On the one hand, maintaining fewer branches is definitely less work, and that leaves more time for developing the next generation of new and interesting features. On the other hand, I'm sure there are people out there chugging happily along on 7.4 and 8.0. Our release support policy says that we aim to "fully support a major release for five years", and while that seems like a long time, in some sense it isn't. It takes some time for new releases to get picked up by operating system distributions, and in some cases it may only get added to new major versions of the OS. So there might conceivably be a year or two between the time when we release and the time when adoption becomes widespread. That's a significant fraction of the total life time of that release.
The good news is that even if the release you're running has now reached its end of life, there's really no reason to panic. It's fair to say that 7.4 and 8.0 are fairly antiquated releases by now. There are tons of improvements in the newer releases, and in particular performance should be much better in PostgreSQL 8.3 and later. On the other hand, if the limitations and/or remaining bugs of the release you're now running haven't bothered you yet, they're probably not going to start bothering you just because we've stopped releasing updates. You should, however, upgrade to 7.4.30 or 8.0.26, and keep an eye out for security issues in future updates of 8.1 and higher that might be relevant to your environment. Eventually, you'll probably want to upgrade, but you don't have to do it tomorrow.
Please leave a comment with your opinion about our release support policy. Is five years too short? Too long? Just right?