PHP has deprecated some functions in latest version. If the same functions are still on your website, you will see following warning message while browsing your website:
Deprecated: Function split() is deprecated in
You can add the following line in the top of your index or bootstrap file.
error_reporting(E_ALL & ~E_NOTICE & ~E_DEPRECATED);
Once you put this, your application will show all the other errors except for Notices and Deprecation errors.