warning

Warning is a non-fatal php error after which execution of the script is continued.

When working with your website, you can sometimes see different types of fatal errors and warnings displayed at your website frontend or in admin panel.

Warning message means that a php script is not running correctly and this can potentially cause fatal errors in the future. The error that it informs you of is not critical and the script execution continues.

It is good if you know the root problem that causes the warning to appear and can address it. But, if you know that the functioning of your website is not disrupted or the warning cannot be avoided for whatever reason, you can just use the error reporting function to turn off the display of warning. This can be done either in your website admin panel or in configuration file of your website (the exact way to do this depends on the type of the website you have).