You can download Zoph from the SourceForge files page.
Which one should I use?
Zoph releases are categorized in 2 groups:
Stable releases are well-tested releases, bugs found in these releases are quickly resolved, especially if they are serious or security bugs. Stable releases have a version number in the form 0.x, for example 0.8.
Bugfix releases for a stable release have the form 0.x.0.y, for example 0.7.0.5, which is the 5th bugfix release for Zoph v0.7.
Unstable releases are bleeding edge releases, in these releases usually the newly added changes have been well-tested, but regression testing has not yet been performed.
There are 2 kinds of unstable releases for Zoph:
Feature releases are interim releases that are meant to show a preview of features that will be available in the next stable release. Between 2 stable releases I usually plan 4 to 6 feature releases, each adding 1 or 2 big features and a few smaller improvements.
Version numbers for feature releases have the form 0.x.y, for example 0.7.4, which is the fourth feature release between 0.7 and 0.8.
Bugfixes for feature releases are only released in case of serious or security problems are usually available later than the stable release, their version number has the form 0.x.y.z, for example 0.7.2.1, which is the first bugfix for 0.7.2 feature release.
Feature releases may require some manual changes to the upgradescript.
Pre-releases are release candidates for an upcoming stable release. This means the next release is feature frozen, i.e. no new features will be added, only bugfixes are made. If no bugs have been found in about 2 weeks after a pre-release, a stable release will come out.
Pre-releases have a version number in the form 0.xprey, for example 0.8pre2, the second pre-release for the 0.8 release.
No really, which one should I use?
This is completely up to you. If you just want a working solution, you're probably best off with a stable release. However, please keep in mind that Zoph cannot exist without people testing the feature- and pre-releases. If you do not dare to run your production Zoph on one of those releases, you might want to consider running a secondary database on an unstable release.