Not compatible with PHP 7.0 and above

The plugin itself is very functional and nicely made, but somehow not compatible with the up to date php versions. I’m getting the following error message above my categories:

Warning: A non-numeric value encountered in?/data/web/virtuals/153331/virtual/www/domains/homepage/wp-content/plugins/collapsing-categories/collapscatlist.php?on line?267

Please fix and update your plugin and I will install it again!

Thank you