This plugin is one of three tiers, this one being Lite, and the others Standard (free "upgrade") and Pro.
You switch to the other version and it replaces it with a non-GPL licensed plugin. Instead of
COPYING.txt there is a
EULA.license. Timely is unable to distribute that plugin in the repository.
The plugin delivers what they promise, more or less, but in a way that I feel is creepy and lacking in transparency. Therefore I can not recommend this plugin.