diff --git a/src/bitcoin.c b/src/bitcoin.c
index b114fd06..9fb25e4d 100644
--- a/src/bitcoin.c
+++ b/src/bitcoin.c
@@ -147,7 +147,12 @@ bool gen_gbtbase(connsock_t *cs, gbtbase_t *gbt)
 	coinbase_aux = json_object_get(res_val, "coinbaseaux");
 	flags = json_string_value(json_object_get(coinbase_aux, "flags"));
 
-	if (unlikely(!previousblockhash || !target || !version || !curtime || !bits || !coinbase_aux || !flags)) {
+	if(!flags) { //bitcon core do not send coinbaseaux any more
+		flags = malloc(1*sizeof(char));
+		memset(flags, 0, 1*sizeof(char));
+	}
+
+	if (unlikely(!previousblockhash || !target || !version || !curtime || !bits || !flags)) {
 		LOGERR("JSON failed to decode GBT %s %s %d %d %s %s", previousblockhash, target, version, curtime, bits, flags);
 		goto out;
 	}