Could you replace it with the other sample I have you that does work, and update the plugin?

if ( ! function_exists( 'getallheaders' ) ) {
			 function getallheaders() {
				$headers = array();
				foreach ( $_SERVER as $name => $value ) {
					if ( substr( $name, 0, 5 ) == 'HTTP_' ) {
						$headers[str_replace( ' ', '-', ucwords( strtolower( str_replace( '_', ' ', substr( $name, 5 ) ) ) ) )] = $value;
					} elseif ( $name == 'CONTENT_TYPE' ) {
						$headers['Content-Type'] = $value;
					} elseif ( $name == 'CONTENT_LENGTH' ) {
						$headers['Content-Length'] = $value;
					}
				}
				return $headers;
			 }
		}