Answer:
No, there is no separate installation file for the viewer mode of RFEM 5 or RSTAB 8. During the installation, a desktop icon with and without the "viewer" addition is created automatically.
There is only one installation file for RFEM 5 or RSTAB 8. Install it—regardless of whether you want to use a licensed version, the viewer mode, or a trial version.
For stand-alone programs (for example, SHAPE‑THIN, CRANEWAY, and so on), there is no viewer mode available.