diff --git a/js/ThreeQuaternionIO.ts b/js/ThreeQuaternionIO.ts
index cf0da4f..9fdb445 100644
--- a/js/ThreeQuaternionIO.ts
+++ b/js/ThreeQuaternionIO.ts
@@ -1,4 +1,4 @@
-// Copyright 2021-2023, University of Colorado Boulder
+// Copyright 2021-2024, University of Colorado Boulder
 
 /**
  * PhET-iO Type for three.js Quaternion type