[Plugin: RDFa Breadcrumb] 3.4.1 compatible?

A client of mine asked me to include RDFa in his site, so I found this plugin. Based on the rating and downloads it’s a very good plugin. However it doesn’t seem to work on my installation.
I installed the plugin with trough the plugins tab (‘add new’), copy-pasted <?php if(function_exists(‘rdfa_breadcrumb’)){ rdfa_breadcrumb(); } ?> into my template and then filled out the settings, but it doesn’t show any content on my site. (https://bit.ly/NlBv9I) It should be right after </div><!– end doer –>

Could it be something with 3.4.1 compatibility or did I do something wrong?

Thanks in advance

https://www.ads-software.com/extend/plugins/rdfa-breadcrumb/