Current release
The most recently announced stable version of OpenMx is version 2.22.x. Click here to read the release announcement. This can be installed from CRAN in the usual way via install.packages("OpenMx").
For all platforms: to install the OpenMx Team's NPSOL enabled build Click here for instructions.
If you've got questions, ask on our forums, or stack overflow.
If you have a suggestion or bug, post on the issues at github.