diff --git a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/subscribe/json/NewHeadMessage.kt b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/subscribe/json/NewHeadMessage.kt
index e1f7662b..85a37798 100644
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/subscribe/json/NewHeadMessage.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/subscribe/json/NewHeadMessage.kt
@@ -41,9 +41,11 @@ data class NewHeadMessage(
     @get:JsonSerialize(using = TimestampSerializer::class)
     val timestamp: Instant,
     @get:JsonSerialize(using = NumberAsHexSerializer::class)
-    val difficulty: BigInteger,
+    @get:JsonInclude(JsonInclude.Include.NON_NULL)
+    val difficulty: BigInteger?,
     @get:JsonSerialize(using = NumberAsHexSerializer::class)
-    val gasLimit: Long,
+    @get:JsonInclude(JsonInclude.Include.NON_NULL)
+    val gasLimit: Long?,
     @get:JsonSerialize(using = NumberAsHexSerializer::class)
     val gasUsed: Long,
     @get:JsonSerialize(using = HexDataSerializer::class)