diff --git a/src/main/java/net/openhft/chronicle/map/VanillaChronicleMap.java b/src/main/java/net/openhft/chronicle/map/VanillaChronicleMap.java
index ee0f24c31..3c494cfcc 100644
--- a/src/main/java/net/openhft/chronicle/map/VanillaChronicleMap.java
+++ b/src/main/java/net/openhft/chronicle/map/VanillaChronicleMap.java
@@ -1416,6 +1416,7 @@ class VanillaChronicleMap<K, KI, MKI extends MetaBytesInterop<K, KI>,
     }
 
     final class WriteThroughEntry extends SimpleEntry<K, V> {
+        private static final long serialVersionUID = 0L;
 
         WriteThroughEntry(K key, V value) {
             super(key, value);
diff --git a/src/main/java/net/openhft/chronicle/map/serialization/BytesReaders.java b/src/main/java/net/openhft/chronicle/map/serialization/BytesReaders.java
index 8f9fa04eb..c0e2e7398 100644
--- a/src/main/java/net/openhft/chronicle/map/serialization/BytesReaders.java
+++ b/src/main/java/net/openhft/chronicle/map/serialization/BytesReaders.java
@@ -26,6 +26,7 @@ public final class BytesReaders {
     }
 
     private static class SimpleBytesReader<E> implements BytesReader<E> {
+        private static final long serialVersionUID = 0L;
 
         private final BytesMarshaller<E> marshaller;