I'm testing a site for a client to upgrade to PHP version 7.1.7 and there is an error that shows in the header after changing PHP versions.
Warning: A non-numeric value encountered in .../wp-content/themes/x/framework/functions/global/admin/thumbnails/width.php on line 74
Running the latest version of X theme 5.1.1
The site running PHP 5.6 does not have this problem and running 7.0 also does not produce the issue so it's a fairly recent change that's causing the issue.
How can we fix this so the site can run on her host's PHP 7.1.7?