I have installed 1.3.1 (twice....!) but it does not work.
I can add testimonials OK.
Nothing is shown either with a shortcode or in a widget.
Indeed, even with the widget correctly in place, no widget is output to any page.
Similarly, a shortcode produced absolutely nothing.
I have looked at previous threads and this appeared to be an issue with 1.3.0 but I am getting it with 1.3.1 and Canvas theme.