diff --git a/core/src/main/java/io/cloudevents/core/impl/BaseCloudEventBuilder.java b/core/src/main/java/io/cloudevents/core/impl/BaseCloudEventBuilder.java
index 3268e70a3..69846c8eb 100644
--- a/core/src/main/java/io/cloudevents/core/impl/BaseCloudEventBuilder.java
+++ b/core/src/main/java/io/cloudevents/core/impl/BaseCloudEventBuilder.java
@@ -213,7 +213,7 @@ protected static IllegalStateException createMissingAttributeException(String at
      *
      * @param name the extension name
      * @return true if extension name is valid, false otherwise
-     * @see <a href="https://github.com/cloudevents/spec/blob/master/spec.md#attribute-naming-convention">attribute-naming-convention</a>
+     * @see <a href="https://github.com/cloudevents/spec/blob/main/cloudevents/spec.md#naming-conventions">attribute-naming-conventions</a>
      */
     private static boolean isValidExtensionName(String name) {
         for (int i = 0; i < name.length(); i++) {