[Plugin: Pretty Pinterest Pins] Getting error message; please help

Hello-

I installed your plugin today, but it is not working for me. I get this error message:

“Fatal error: Call to undefined function wp_trim_words() in /home/site5/public_html/wp-content/plugins/pretty-pinterest-pins/pretty-pinterest-pins.php on line 153”

Any idea why this is happening and what we can do to fix it?

Thank you.

https://www.ads-software.com/extend/plugins/pretty-pinterest-pins/