diff --git a/modules/chain/dap_chain_ledger.c b/modules/chain/dap_chain_ledger.c
index bf55dd1b97afa257ae2b159615006c22627fd557..b44bad7c8d3b749ee33e74a6f76bb4f382171a3b 100644
--- a/modules/chain/dap_chain_ledger.c
+++ b/modules/chain/dap_chain_ledger.c
@@ -2856,11 +2856,11 @@ dap_hash_fast_t *dap_chain_ledger_get_final_chain_tx_hash(dap_ledger_t *a_ledger
 /**
  * Check whether used 'out' items (local function)
  */
-static dap_hash_fast_t *s_ledger_tx_hash_is_used_out_item(dap_chain_ledger_tx_item_t *a_item, int a_idx_out)
+static bool s_ledger_tx_hash_is_used_out_item(dap_chain_ledger_tx_item_t *a_item, int a_idx_out)
 {
     if (!a_item || !a_item->cache_data.n_outs) {
         //log_it(L_DEBUG, "list_cached_item is NULL");
-        return NULL;
+        return false;
     }
     if(a_idx_out >= MAX_OUT_ITEMS) {
         if(s_debug_more)
@@ -2871,9 +2871,9 @@ static dap_hash_fast_t *s_ledger_tx_hash_is_used_out_item(dap_chain_ledger_tx_it
     if(a_item->cache_data.n_outs_used > 0) {
         dap_hash_fast_t *l_hash_used = &(a_item->cache_data.tx_hash_spent_fast[a_idx_out]);
         if(!dap_hash_fast_is_blank(l_hash_used))
-            return l_hash_used;
+            return true;
     }
-    return NULL;
+    return false;
 }
 
 /**
@@ -4420,7 +4420,7 @@ size_t dap_chain_ledger_count_tps(dap_ledger_t *a_ledger, struct timespec *a_ts_
 /**
  * Check whether used 'out' items
  */
-dap_chain_hash_fast_t *dap_chain_ledger_tx_hash_is_used_out_item(dap_ledger_t *a_ledger, dap_chain_hash_fast_t *a_tx_hash, int a_idx_out)
+bool dap_chain_ledger_tx_hash_is_used_out_item(dap_ledger_t *a_ledger, dap_chain_hash_fast_t *a_tx_hash, int a_idx_out)
 {
     dap_chain_ledger_tx_item_t *l_item_out = NULL;
     //dap_chain_datum_tx_t *l_tx =
diff --git a/modules/chain/include/dap_chain_ledger.h b/modules/chain/include/dap_chain_ledger.h
index 86aa6b97b08be5eb7eda5545542ee4a1d32f2bc9..8c7514dc6c6c5079f47dc8a89485801dae3ddcc8 100644
--- a/modules/chain/include/dap_chain_ledger.h
+++ b/modules/chain/include/dap_chain_ledger.h
@@ -202,7 +202,7 @@ void dap_chain_ledger_set_tps_start_time(dap_ledger_t *a_ledger);
 /**
  * Check whether used 'out' items
  */
-dap_chain_hash_fast_t *dap_chain_ledger_tx_hash_is_used_out_item(dap_ledger_t *a_ledger, dap_chain_hash_fast_t *a_tx_hash, int a_idx_out);
+bool dap_chain_ledger_tx_hash_is_used_out_item(dap_ledger_t *a_ledger, dap_chain_hash_fast_t *a_tx_hash, int a_idx_out);
 
 /**
  * Calculate balance of addr
diff --git a/modules/service/stake_pos_delegate/dap_chain_net_srv_stake_pos_delegate.c b/modules/service/stake_pos_delegate/dap_chain_net_srv_stake_pos_delegate.c
index e744a8f50d86382b9c9b73fd0c9d41fafd30dfc4..a83b0b5c9e2cdf34419d2e838573a0a63ebc5d58 100644
--- a/modules/service/stake_pos_delegate/dap_chain_net_srv_stake_pos_delegate.c
+++ b/modules/service/stake_pos_delegate/dap_chain_net_srv_stake_pos_delegate.c
@@ -1121,8 +1121,7 @@ static void s_get_tx_filter_callback(dap_chain_net_t* a_net, dap_chain_datum_tx_
                                                                  &l_out_idx_tmp)))
     {
         dap_hash_fast(a_tx, dap_chain_datum_tx_get_size(a_tx), &l_datum_hash);
-        if(dap_chain_ledger_tx_hash_is_used_out_item(a_net->pub.ledger,&l_datum_hash,l_out_idx_tmp)==NULL)
-        {
+        if (!dap_chain_ledger_tx_hash_is_used_out_item(a_net->pub.ledger, &l_datum_hash, l_out_idx_tmp)) {
             dap_chain_net_srv_stake_item_t *l_stake = NULL;
             HASH_FIND(ht, s_srv_stake->tx_itemlist, &l_datum_hash, sizeof(dap_hash_fast_t), l_stake);
             if(!l_stake){
diff --git a/modules/service/xchange/dap_chain_net_srv_xchange.c b/modules/service/xchange/dap_chain_net_srv_xchange.c
index e62e93e932566d1ef9bcafac29f77f1dd81b77e9..2dac02ab5511eb7f64a7b2d19b3eaad0b684b0e4 100644
--- a/modules/service/xchange/dap_chain_net_srv_xchange.c
+++ b/modules/service/xchange/dap_chain_net_srv_xchange.c
@@ -1543,7 +1543,7 @@ dap_chain_hash_fast_t l_tx_first_hash = {0};
 dap_chain_datum_tx_t    *l_datum_tx;
 size_t  l_datum_tx_size, l_tx_total, l_tx_count;
 int l_item_idx;
-dap_hash_fast_t *l_rc;
+bool l_rc;
 dap_string_t *l_reply_str;
 dap_hash_fast_t l_hash;
 dap_chain_tx_out_cond_t *l_out_cond_item;
@@ -1635,7 +1635,7 @@ static int s_cli_srv_xchange(int a_argc, char **a_argv, char **a_str_reply)
 {
     enum {CMD_NONE = 0, CMD_ORDER, CMD_ORDERS, CMD_PURCHASE, CMD_ENABLE, CMD_DISABLE, CMD_TX_LIST, CMD_TOKEN_PAIR };
     int l_arg_index = 1, l_cmd_num = CMD_NONE;
-    dap_hash_fast_t *l_rc;
+    bool l_rc;
 
     if(dap_cli_server_cmd_find_option_val(a_argv, l_arg_index, min(a_argc, l_arg_index + 1), "order", NULL)) {
         l_cmd_num = CMD_ORDER;