Add release notes wrt #2251
diff --git a/release-notes/VERSION-2.x b/release-notes/VERSION-2.x
index f868edf..cb34c4a 100644
--- a/release-notes/VERSION-2.x
+++ b/release-notes/VERSION-2.x
@@ -11,6 +11,7 @@
#2221: `DeserializationProblemHandler.handleUnknownTypeId()` returning `Void.class`,
enableDefaultTyping causing NPE
(reported by MeyerNils@github)
+#2251: Getter that returns an abstract collection breaks a delegating `@JsonCreator`
- Prevent String coercion of `null` in `WritableObjectId` when calling `JsonGenerator.writeObjectId()`,
mostly relevant for formats like YAML that have native Object Ids