Recently, we’ve noticed that many of our clients website that runs LayerSlider Responsive WordPress Slider Plugin is having an issue with an updated version.
The problem is that as soon as the plugin is updated, you will see a php error message appearing at the top of the page where you are running the layer slider.
The error message points to an Call to undefined function.. mb_ereg_match().
Causes for call to underfined function mb_ereg_match()
As with the most WordPress errors, the issue is rather simple. If it is not the plugin that is broken, it has to be the version of PHP, WordPress, or some settings on your web server. What we have found as the potential cause for the issue is as it follows:
1. Old version of PHP running the WordPress. PHP version 5 and later has the full support or mb_ereg which allows running multibyte regular expression function.
2. mbstring extension is not enabled. You can refer to this guide for installing the mbstring php extension or contact your web hosting company or server administrator to simply have it done for you.
3. If you are running php version 5.x or later and mbstring extension is installed and still having the issue, it is most likely that the Multibyte Regex is not enabled. In most cases, this comes by default with the installation of mbstring php extension, but it is very possible that Multibyte eregi and Multibyte Regex is not enabled. You can also contact the support and make sure they are enabled on your server.
Hope this information help.