Bennycopter

More info about the issue:

https://php.watch/versions/8.0/non-static-static-call-fatal-error

I was able to fix this issue on our end by changing the method declaration from public function maybe_display_floating_button() to public static function maybe_display_floating_button(). (Ko_fi.php, line 262)

I experienced the issue as well. Here’s the error message from it.

PHP version: 8.1.2

WordPress version: 6.2

Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, non-static method Ko_Fi::maybe_display_floating_button() cannot be called statically in /var/www/(domain)/html/wp-includes/class-wp-hook.php:308
Stack trace:
0 /var/www/(domain)/html/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters()
1 /var/www/(domain)/html/wp-includes/plugin.php(517): WP_Hook->do_action()
2 /var/www/(domain)/html/wp-includes/general-template.php(3049): do_action()
3 /var/www/(domain)/html/wp-content/themes/kadence/header.php(24): wp_head()
4 /var/www/(domain)/html/wp-includes/template.php(783): require_once('…')
5 /var/www/(domain)/html/wp-includes/template.php(718): load_template()
6 /var/www/(domain)/html/wp-includes/general-template.php(48): locate_template()
7 /var/www/(domain)/html/wp-content/themes/kadence/page.php(14): get_header()
8 /var/www/(domain)/html/wp-includes/template-loader.php(106): include('…')
9 /var/www/(domain)/html/wp-blog-header.php(19): require_once('…')
10 /var/www/(domain)/html/index.php(17): require('…')
11 {main}
thrown in /var/www/(domain)/html/wp-includes/class-wp-hook.php on line 308