The plugin requires CMB2, but if one installs plugin on WP <4.4 it will install and request CMB2 be installed, but once installed the admin area goes away and one gets an error message that WP Term Data is a feature of WP 4.4.
Technically, I suppose, this is an issue with CMB2. Logic could be added to CMB2 or to this plugin to check.
The plugin requires CMB2, but if one installs plugin on WP <4.4 it will install and request CMB2 be installed, but once installed the admin area goes away and one gets an error message that WP Term Data is a feature of WP 4.4.
Technically, I suppose, this is an issue with CMB2. Logic could be added to CMB2 or to this plugin to check.
Easy to fix - delete CMB2 plugin.