$entries = []; syntax error

Question

Hello This may be a simple question but I am a beginner at php, any help would be greatly appreciated. I am receiving a syntax error in my code at the line where I have $entries = []; I'm not sure why.

I am new to php so I researched and found out that the [] are arrays but I'm not sure why they are empty or why I am receiving an error. prior to this error I was trying to update plugins on wordpress, then shortly after the site went blank white space and provided this error

Parse error: syntax error, unexpected '[' in /var/www/ctf/wp-content/plugins/user-registration-aide/views/ura-debug.php on line 53

so when I navigated to the file and to the line where the error is i saw this

function debug_log_data(){
        $sep = '$!$';
        $entries = []; 
        $log = WP_CONTENT_DIR . '/debug.log';
        if ( file_exists( $log ) ){
            $fp = @fopen( $log, 'r');

            if ($fp) {
                while ( ( $line = @fgets( $fp ) ) !== false ) {
                    $line = preg_replace( "/^\[([0-9a-zA-Z-]+) ([0-9:]+) ([a-zA-Z_\/]+)\] (.*)$/i", "$1".$sep."$2".$sep."$3".$sep."$4", $line );
                    $parts = explode( $sep, $line );

                    if ( count( $parts ) >= 4 ) {
                        $entries[] = [
                            'date' => date( 'Y/m/d', strtotime( $parts[0] ) ),
                            'time' => $parts[1],
                            'timezone' => $parts[2],
                            'message' => stripslashes( $parts[3] ),
                        ];
                    }
                }

                @fclose( $fp );
            }
        }

        return array_reverse( $entries );
    }
//}

I'm not sure what the problem is but any help would be appreciated. Thank you for your time.