diff --git a/openair-cn/NAS/EURECOM-NAS/src/api/user/at_response.c b/openair-cn/NAS/EURECOM-NAS/src/api/user/at_response.c
index 0dbea18911d3feef3fca3086cfef913ab6f3485e..c0c9970ab8ffcc3836be09e848f04592abfe5158 100644
--- a/openair-cn/NAS/EURECOM-NAS/src/api/user/at_response.c
+++ b/openair-cn/NAS/EURECOM-NAS/src/api/user/at_response.c
@@ -491,6 +491,7 @@ static int _at_response_encode_clac(char* buffer, const at_response_t* data)
 
     const at_clac_resp_t * clac = &(data->response.clac);
     int offset = 0;
+    int i;
 
     if (data->type == AT_COMMAND_ACT) {
 	if (clac->n_acs > 0) {
@@ -498,7 +499,7 @@ static int _at_response_encode_clac(char* buffer, const at_response_t* data)
 		offset += sprintf(buffer, "\r\n");
 	    }
 	    offset += sprintf(buffer+offset, "%s", clac->ac[0]);
-	    for (int i = 1; i < clac->n_acs; i++) {
+	    for (i = 1; i < clac->n_acs; i++) {
 		offset += sprintf(buffer+offset, "\r\n%s", clac->ac[i]);
 	    }
 	}
@@ -872,6 +873,7 @@ static int _at_response_encode_cgdcont(char* buffer, const at_response_t* data)
     LOG_FUNC_IN;
 
     int offset = 0;
+    int i;
 
     if (data->type == AT_COMMAND_GET)
     {
@@ -881,7 +883,7 @@ static int _at_response_encode_cgdcont(char* buffer, const at_response_t* data)
 	}
 
 	/* Display the list of defined PDN contexts */
-	for (int i = 0; i < cgdcont->n_pdns; i++) {
+	for (i = 0; i < cgdcont->n_pdns; i++) {
 	    offset += sprintf(buffer+offset, "+CGDCONT: %u", cgdcont->cid[i]);
 	    if (cgdcont->PDP_type[i] == NET_PDN_TYPE_IPV4) {
 		offset += sprintf(buffer+offset, ",IP");
@@ -950,6 +952,7 @@ static int _at_response_encode_cgact(char* buffer, const at_response_t* data)
     LOG_FUNC_IN;
 
     int offset = 0;
+    int i;
 
     if (data->type == AT_COMMAND_GET)
     {
@@ -958,7 +961,7 @@ static int _at_response_encode_cgact(char* buffer, const at_response_t* data)
 	    offset += sprintf(buffer, "\r\n");
 	}
 	/* Display the list of defined PDN status */
-	for (int i = 0; i < cgact->n_pdns; i++) {
+	for (i = 0; i < cgact->n_pdns; i++) {
 	    offset += sprintf(buffer+offset, "+CGACT: %u,%u\r\n",
 			      cgact->cid[i], cgact->state[i]);
 	}
@@ -996,6 +999,7 @@ static int _at_response_encode_cgpaddr(char* buffer, const at_response_t* data)
 
     int offset = 0;
     const at_cgpaddr_resp_t * cgpaddr = &(data->response.cgpaddr);
+    int i;
 
     if (data->type == AT_COMMAND_SET)
     {
@@ -1004,7 +1008,7 @@ static int _at_response_encode_cgpaddr(char* buffer, const at_response_t* data)
 	}
 	/* Display the list of IP addresses assigned to each defined PDN
 	 * connections */
-	for (int i = 0; i < cgpaddr->n_pdns; i++) {
+	for (i = 0; i < cgpaddr->n_pdns; i++) {
 	    offset += sprintf(buffer+offset, "+CGPADDR: %u", cgpaddr->cid[i]);
 	    if (cgpaddr->PDP_addr_1[i] != NULL) {
 		/* IPv4 address */
@@ -1042,7 +1046,7 @@ static int _at_response_encode_cgpaddr(char* buffer, const at_response_t* data)
 		offset += sprintf(buffer, "\r\n");
 	    }
 	    offset += sprintf(buffer+offset, "+CGPADDR: %u", cgpaddr->cid[0]);
-	    for (int i = 1; i < cgpaddr->n_pdns; i++) {
+	    for (i = 1; i < cgpaddr->n_pdns; i++) {
 		offset += sprintf(buffer+offset, ",%u", cgpaddr->cid[i]);
 	    }
 	    offset += sprintf(buffer+offset, "\r\n");
diff --git a/openair-cn/NAS/EURECOM-NAS/src/api/usim/usim_api.c b/openair-cn/NAS/EURECOM-NAS/src/api/usim/usim_api.c
index 11399074a42a2fa5d3123ff20bdbf55a4a382de7..e228f3c56139d9219a47ebf1e040bdfa8c07e8fc 100644
--- a/openair-cn/NAS/EURECOM-NAS/src/api/usim/usim_api.c
+++ b/openair-cn/NAS/EURECOM-NAS/src/api/usim/usim_api.c
@@ -190,6 +190,7 @@ int usim_api_authenticate(const OctetString* rand, const OctetString* autn,
     LOG_FUNC_IN;
 
     int rc;
+    int i;
 
     /* Compute the authentication response RES = f2K (RAND) */
     /* Compute the cipher key CK = f3K (RAND) */
@@ -203,7 +204,7 @@ int usim_api_authenticate(const OctetString* rand, const OctetString* autn,
     /* Retrieve the sequence number SQN = (SQN ⊕ AK) ⊕ AK */
 #define USIM_API_SQN_SIZE USIM_API_AK_SIZE
     u8 sqn[USIM_API_SQN_SIZE];
-    for (int i = 0; i < USIM_API_SQN_SIZE; i++) {
+    for (i = 0; i < USIM_API_SQN_SIZE; i++) {
 	sqn[i] = rand->value[i] ^ ak[i];
     }
 
@@ -234,13 +235,13 @@ int usim_api_authenticate(const OctetString* rand, const OctetString* autn,
 	u8 sqn_ms[USIM_API_SQNMS_SIZE];
 	memset(sqn_ms, 0, USIM_API_SQNMS_SIZE);
 #define USIM_API_SQN_MS_SIZE	3
-	for (int i = 0; i < USIM_API_SQN_MS_SIZE; i++) {
+	for (i = 0; i < USIM_API_SQN_MS_SIZE; i++) {
 	    sqn_ms[USIM_API_SQNMS_SIZE - i] =
 		((UInt8_t*)(_usim_api_data.sqn_ms))[USIM_API_SQN_MS_SIZE - i];
 	}
 
 	u8 sqnms[USIM_API_SQNMS_SIZE];
-	for (int i = 0; i < USIM_API_SQNMS_SIZE; i++) {
+	for (i = 0; i < USIM_API_SQNMS_SIZE; i++) {
 	    sqnms[i] = sqn_ms[i] ^ ak[i];
 	}