PHP 8.0 issue with widget includes?

I suspect the cause is a theme or plugin you are using. Can you have a detailed error log entry output? The debug mode can help: https://www.ads-software.com/support/article/debugging-in-wordpress/

What version of WordPress are you using? A version older than 5.6 would generate that error with PHP 8.0. Here’s more info about WordPress/PHP compatibility:

https://make.www.ads-software.com/core/handbook/references/php-compatibility-and-wordpress-versions

Thanks @diondesigns all plugins and themes and WordPress core are at their most recent version, so core is 6.0.2, so unfortunately that’s not the issue.

@threadi I tried defaulting back to default theme “Twenty Twenty-One” and the error still persists, so I don’t think it’s a Theme issue… plus the sites I’m working with are all using different themes.

I think with one of the sites, I have discovered this plugin to be the culprit, so I have removed it: https://www.ads-software.com/plugins/facebook-like-box-widget/

Unfortunately the sites don’t share many plugins in common either… I shall keep investigating…

Take a website that is affected and deactivate all plugins as a test. Then activate them one by one until the error occurs again. This way you should be able to find the culprit. The plugin https://www.ads-software.com/plugins/health-check/ can also help with the troubleshoot mode.

@threadi Yes I’ve been trying this method as well, but even with all plugins deactivated and wordpress default theme Twenty Twenty One activated, the site still gives a critical error when I try to upgrade to PHP 8.0… very frustrating…

I cannot reproduce this in a fresh installation. Can you please check if you have any widgets in use? Maybe one of them is the disturbing one. Simply removing all of them would be a possibility.

It looks like one site is using a highly customized version of the WordPress Twenty-Eleven theme, so I’m just gonna go ahead and suggest a rebuild on that one, it’s so old it needs it. Thanks anyway @threadi