On this page are links to the documentation from our current release, and from OpenMDAO’s older versions as well.
For somewhat older builds, from OpenMDAO 2.0 through 3.9.2, documentation can be found here.
To see documentation from the stable and usable 1.7.3 (and any other versions of 1.x.y), visit readthedocs. (Other, older 1.x.y versions, are available in the lower-right corner drop-down menu.)
To see documentation from the 0.x.y days…we’ll, we’d recommend against it, because we no longer support it! But if you’re dead-set on running the vintage stuff, you can find it deep in our archives.