Fatal error : settings.php on line 87 in Version 1.55

Have been using shift8 cdn for some years, did change my site to use https and needed to change the adress link in the settings, did get a error. So deleted my account and created a new site, and get the same error when saving at my wordpress site.

Yes I have filed in all fields needed
Wordpress version = 5.7.1
shit8 version = 1.55

Fatal error : Uncaught Error: Undefined constant “FILTER_FLAG_SCHEME_REQUIRED” in /var/www/site.se/public_html/wp-content/plugins/shift8-cdn/components/settings.php:87 Stack trace: #0 /var/www/site.se/public_html/wp-includes/class-wp-hook.php(294): shift8_cdn_url_validate() #1 /var/www/site.se/public_html/wp-includes/plugin.php(212): WP_Hook->apply_filters() #2 /var/www/site.se/public_html/wp-includes/formatting.php(4907): apply_filters() #3 /var/www/site.se/public_html/wp-includes/option.php(369): sanitize_option() #4 /var/www/site.se/public_html/wp-admin/options.php(314): update_option() #5 {main} thrown in /var/www/site.se/public_html/wp-content/plugins/shift8-cdn/components/settings.php on line 87

I am facing the same problem, :wink: did you find the solution?

Hey guys!

I believe you would be seeing this error if you are utilizing PHP 8 with the site. Our plugin is referencing to a constant that was removed in php 8 (reference : `FILTER_FLAG_SCHEME_REQUIRED` and `FILTER_FLAG_HOST_REQUIRED` flags are removed - PHP 8.0 • PHP.Watch).

A full PHP 8 audit and compatibility effort still needs to be done. The idea was to wait a bit longer to ensure that everything else with Wordpress becomes a bit more stable than when it first was released. Unfortunately at this point I would say the best way to move forward would be to use latest PHP 7 with our plugin.


The way forward is to fix the compatibility issues this plugin has with PHP 8. The newest Shift8 CDN plugin V1.55 still does not function with PHP 8. More resources should going to troubleshoot these PHP8 issues. I think this is the best cdn plugin I have used to date. I am so sorry that the newest Shift8 CDN plugin still does not function with PHP 8.

You are correct - i will shift and divert resources this week to supporting compatibility with php8.

An announcement will be made when the issues are resolved.

Thank you for your patience.


An update was pushed out (v1.56) to deal with this fatal error that is happening in PHP 8. It should resolve the issue for you here but please let me know if anything else comes up.

Thanks for your patience!

Now it works to load the plugin, but get a warning messages on the plugin

Warning : Undefined array key “path” in /var/www/sitename.se/public_html/wp-content/plugins/shift8-cdn/shift8-cdn.php on line 143

The compatibility issues seem to be fixed with this plugin and PHP 8. The newest Shift8 CDN plugin V1.57 is a keeper. Thanks for all you’ve done kevinnivek.