diff --git a/src/main/java/com/conveyal/r5/kryo/KryoNetworkSerializer.java b/src/main/java/com/conveyal/r5/kryo/KryoNetworkSerializer.java
index 67298b1bc..619691e76 100644
--- a/src/main/java/com/conveyal/r5/kryo/KryoNetworkSerializer.java
+++ b/src/main/java/com/conveyal/r5/kryo/KryoNetworkSerializer.java
@@ -46,7 +46,8 @@ public abstract class KryoNetworkSerializer {
      * We considered using an ISO date string as the version but that could get confusing when seen in filenames.
      *
      * History of Network Version (NV) changes:
-     * nv3 use Kryo 5 serialization format
+     * nv4 2023-11-02 WebMercatorGridPointSet now contains nested WebMercatorExtents
+     * nv3 2023-18-01 use Kryo 5 serialization format
      * nv2 2022-04-05
      * nv1 2021-04-30 stopped using r5 version string (which caused networks to be rebuilt for every new r5 version)
      */