Critical error <PHP 8.0

PHP 7.4 and older have reached their end of life, but many sites still run them. If they do, they'll get:
PHP Parse error: syntax error, unexpected '|', expecting variable (T_VARIABLE) in /wp-content/plugins/progress-bar/functions.php on line 217

You're right and I should probably add a PHP compatibility checker to ensure backwards compatibility. 👍

Thank you for the prompt fix!