diff --git a/README.md b/README.md
index 8bf8c39..cbc5734 100644
--- a/README.md
+++ b/README.md
@@ -49,6 +49,9 @@ sealed trait Page
 case class UserPage(userId: Int) extends Page
 case object LoginPage extends Page
 
+// For upickle 3 series an explicit derivation of case objects is required
+// case object LoginPage extends Page derives ReadWriter
+
 implicit val UserPageRW: ReadWriter[UserPage] = macroRW
 implicit val rw: ReadWriter[Page] = macroRW