diff --git a/avro/pom.xml b/avro/pom.xml
index 61f591a6..8ebd53e5 100644
--- a/avro/pom.xml
+++ b/avro/pom.xml
@@ -61,7 +61,6 @@ abstractions.
     <dependency>
       <groupId>org.assertj</groupId>
       <artifactId>assertj-core</artifactId>
-      <version>3.11.1</version>
       <scope>test</scope>
     </dependency>
   </dependencies>
diff --git a/release-notes/CREDITS-2.x b/release-notes/CREDITS-2.x
index 2c1760e6..8430cd46 100644
--- a/release-notes/CREDITS-2.x
+++ b/release-notes/CREDITS-2.x
@@ -338,3 +338,7 @@ Joachim Lous (@jlous)
  * Requested #494: Avro Schema generation: allow mapping Java Enum properties to
    Avro String values
   (2.18.0)
+
+Robert Noack (@mr-robert)
+ * Reported #509: IonValueMapper.builder() not implemented, does not register modules
+  (2.18.0)
diff --git a/release-notes/VERSION-2.x b/release-notes/VERSION-2.x
index e57ac110..3d268600 100644
--- a/release-notes/VERSION-2.x
+++ b/release-notes/VERSION-2.x
@@ -24,6 +24,8 @@ Active maintainers:
  (contributed by Michal F)
 #508: (avro) Ignore `specificData` field on serialization
  (contributed by @pjfanning)
+#509: IonValueMapper.builder() not implemented, does not register modules
+ (reported by Robert N)
 
 2.17.3 (not yet released)