The kill() method has been removed from PECL pthreads library version 3. See manual from archive: https://web.archive.org/web/20210410123359/https://www.php.net/manual/en/thread.kill.php Warning: This method has been removed in pthreads v3. Warning: The programmer should not ordinarily kill Threads by force. So as you can see removed in new version: https://www.php.net/manual/en/class.thread.php Now what’s alternate for kill or terminate the proccess from out of class that