Alternative Install
The FEMAddOns release comes in the form of a .paclet file, which contains the entire package and its documentation. Download the latest release from the Github repo's releases page. To install, run the following command in the Wolfram Language:
PacletInstall["/full/path/to/FEMAddOns.paclet"]
Subsequent installs
If you have a previous version (>=1.3.0) of the FEMAddOns installed you can use
Needs["FEMAddOns`"]
UpdateFEMAddOns[]
to update to the latest version.