Error: Call to undefined function get_current_screen()

Hello, Thank you for the plugin. I used it for a year but recently, I notice the following error message in the error log: [162.158.151.247:34320] [STDERR] PHP Fatal error: Uncaught Error: Call to undefined function get_current_screen() in /public_html/wp-content/plugins/scheduled-post-guardian/scheduled-post-guardian.php:89 Stack trace: #0 /public_html/wp-includes/plugin.php(235): Scheduled_Post_Guardian_Plugin->run_on_edit_dot_php(false) #1 /public_html/wp-content/plugins/scheduled-post-guardian/scheduled-post-guardian.php(59): apply_filters(‘scheduled_post_…’, false) #2 /public_html/wp-includes/plugin.php(524): Scheduled_Post_Guardian_Plugin->shutdown(”) #3 /public_html/wp-includes/load.php(671): do_action(‘shutdown’) #4 [internal function]: shutdown_action_hook() #5 {main} thrown in //public_html/wp-content/plugins/scheduled-post-guardian/scheduled-post-guardian.php on line 89 I use PHP7.0. Could you please take a look? Thank you.