When we designate a version with an 'x', such as NEMS 1.2.x, we mean anything within the 1.2 rolling release cycle. This means 1.2 (which can also be considered 1.2.0 if desired), 1.2.1, 1.2.2, and so-on.
A rolling release is a second decimal point release, and rolling upgrades are available within each major release as made available. Rolling releases are usually pushed out in order to fix bugs or improve features. An example of a rolling release would be going from NEMS 1.2 to 1.2.1, or 1.2.1 to 1.2.3. Once a new NEMS major release is available, it is recommended to perform a major release upgrade to ensure you have the latest and greatest NEMS has to offer.
Please Note: If you receive a notice that nems-upgrade is an unknown program, did you initialize NEMS? Please re-read the Installation Instructions if that is the case.
These steps may be followed to upgrade from one major point release to the next major point release. For example, this process will take you from NEMS 1.1 to NEMS 1.2, or NEMS 1.2.x to NEMS 1.3, or ultimately, NEMS 1.3 to 2.0, and so-on.
See legacy upgrade documentation here: http://www.baldnerd.com/nems-migrator-legacy-upgrade/