diff --git a/src/Trace/Propagator/BinaryFormatter.php b/src/Trace/Propagator/BinaryFormatter.php
index d805f13f3..451f8f533 100644
--- a/src/Trace/Propagator/BinaryFormatter.php
+++ b/src/Trace/Propagator/BinaryFormatter.php
@@ -59,7 +59,7 @@ public function deserialize($bin)
      */
     public function serialize(SpanContext $context)
     {
-        $spanHex = str_pad($context->spanId(), 16, "0", STR_PAD_LEFT);
+        $spanHex = str_pad($context->spanId() ?? "", 16, "0", STR_PAD_LEFT);
         $traceOptions = $context->enabled() ? self::OPTION_ENABLED : 0;
         return pack("CCH*CH*CC", 0, 0, $context->traceId(), 1, $spanHex, 2, $traceOptions);
     }
diff --git a/src/Trace/SpanContext.php b/src/Trace/SpanContext.php
index 3bd9b9b03..b76071819 100644
--- a/src/Trace/SpanContext.php
+++ b/src/Trace/SpanContext.php
@@ -52,6 +52,8 @@ class SpanContext
      */
     private $enabled;
 
+	private ?bool $fromHeader;
+
     /**
      * Creates a new SpanContext instance
      *