diff --git a/src/apps/snmp/snmp_msg.c b/src/apps/snmp/snmp_msg.c
index 32c3a747..c44ea8ee 100644
--- a/src/apps/snmp/snmp_msg.c
+++ b/src/apps/snmp/snmp_msg.c
@@ -77,9 +77,9 @@ snmp_version_enabled(u8_t version)
 {
   LWIP_ASSERT("Invalid SNMP version", (version == SNMP_VERSION_1) || (version == SNMP_VERSION_2c)
 #if LWIP_SNMP_V3
-	  || (version == SNMP_VERSION_3)
+     || (version == SNMP_VERSION_3)
 #endif
-	  );
+  );
 
   if (version == SNMP_VERSION_1) {
     return v1_enabled;
@@ -117,19 +117,19 @@ snmp_version_enable(u8_t version, u8_t enable)
 {
   LWIP_ASSERT("Invalid SNMP version", (version == SNMP_VERSION_1) || (version == SNMP_VERSION_2c)
 #if LWIP_SNMP_V3
-	  || (version == SNMP_VERSION_3)
+     || (version == SNMP_VERSION_3)
 #endif
-	  );
+    );
 
   if (version == SNMP_VERSION_1) {
-	v1_enabled = enable;
+    v1_enabled = enable;
   }
   else if (version == SNMP_VERSION_2c) {
-	v2c_enabled = enable;
+    v2c_enabled = enable;
   }
 #if LWIP_SNMP_V3
   else { /* version == SNMP_VERSION_3 */
-	v3_enabled = enable;
+    v3_enabled = enable;
   }
 #endif
 }
@@ -917,7 +917,7 @@ snmp_parse_inbound_frame(struct snmp_request *request)
     IF_PARSE_ASSERT(parent_tlv_value_len > 0);
     /* Remember position */
     inbound_msgAuthenticationParameters_offset = pbuf_stream.offset;
-	LWIP_UNUSED_ARG(inbound_msgAuthenticationParameters_offset);
+    LWIP_UNUSED_ARG(inbound_msgAuthenticationParameters_offset);
     /* Read auth parameters */
     /* IF_PARSE_ASSERT(tlv.value_len <= SNMP_V3_MAX_AUTH_PARAM_LENGTH); */
     IF_PARSE_EXEC(snmp_asn1_dec_raw(&pbuf_stream, tlv.value_len, request->msg_authentication_parameters,
diff --git a/src/apps/snmp/snmp_snmpv2_usm.c b/src/apps/snmp/snmp_snmpv2_usm.c
index 32f5cf6e..88ced2a5 100644
--- a/src/apps/snmp/snmp_snmpv2_usm.c
+++ b/src/apps/snmp/snmp_snmpv2_usm.c
@@ -57,7 +57,7 @@ static u8_t snmp_name_to_oid(const char *name, u32_t *oid, u8_t len)
   u8_t i;
 
   for (i = 0; i < len; i++) {
-	oid[i] = name[i];
+    oid[i] = name[i];
   }
 
   return len;
@@ -203,22 +203,22 @@ static snmp_err_t usmusertable_get_next_instance(const u32_t *column, struct snm
     engineid_start = 1;
 
     if (engineid_len != eid_len) {
-	  /* EngineID length does not match! */
-	  return SNMP_ERR_NOSUCHINSTANCE;
+      /* EngineID length does not match! */
+      return SNMP_ERR_NOSUCHINSTANCE;
     }
 
     if (engineid_len > row_oid->len) {
       /* Verify partial EngineID */
       snmp_engineid_to_oid(engineid, engineid_oid, row_oid->len - 1);
       if (!snmp_oid_equal(&row_oid->id[engineid_start], row_oid->len - 1, engineid_oid, row_oid->len - 1)) {
-	    return SNMP_ERR_NOSUCHINSTANCE;
+        return SNMP_ERR_NOSUCHINSTANCE;
       }
     }
     else {
       /* Verify complete EngineID */
       snmp_engineid_to_oid(engineid, engineid_oid, engineid_len);
       if (!snmp_oid_equal(&row_oid->id[engineid_start], engineid_len, engineid_oid, engineid_len)) {
-	    return SNMP_ERR_NOSUCHINSTANCE;
+        return SNMP_ERR_NOSUCHINSTANCE;
       }
     }
 
@@ -230,8 +230,8 @@ static snmp_err_t usmusertable_get_next_instance(const u32_t *column, struct snm
       name_start = engineid_start + engineid_len + 1;
 
       if (name_len > SNMP_V3_MAX_USER_LENGTH) {
-	    /* specified name is too long, max length is 32 according to mib file.*/
-	    return SNMP_ERR_NOSUCHINSTANCE;
+        /* specified name is too long, max length is 32 according to mib file.*/
+        return SNMP_ERR_NOSUCHINSTANCE;
       }
 
       if (row_oid->len < engineid_len + name_len + 2) {
@@ -245,7 +245,7 @@ static snmp_err_t usmusertable_get_next_instance(const u32_t *column, struct snm
         /* Full name given according to oid. Also test for too much data.*/
         u8_t tmplen = row_oid->len - engineid_len - 2;
         if (!snmp_oid_in_range(&row_oid->id[name_start], name_len, usmUserTable_oid_ranges, tmplen)) {
-	      return SNMP_ERR_NOSUCHINSTANCE;
+          return SNMP_ERR_NOSUCHINSTANCE;
         }
       }
 
diff --git a/src/include/lwip/apps/snmp_opts.h b/src/include/lwip/apps/snmp_opts.h
index 67d2cdd5..96756e53 100644
--- a/src/include/lwip/apps/snmp_opts.h
+++ b/src/include/lwip/apps/snmp_opts.h
@@ -279,7 +279,7 @@
  * THIS IS UNDER DEVELOPMENT AND SHOULD NOT BE ENABLED IN PRODUCTS.
  */
 #ifndef LWIP_SNMP_V3
-#define LWIP_SNMP_V3               0
+#define LWIP_SNMP_V3               1
 #endif
 
 #ifndef LWIP_SNMP_V3_MBEDTLS