diff --git a/src/api/tcpip.c b/src/api/tcpip.c
index b71fb96d..9ef07b8b 100644
--- a/src/api/tcpip.c
+++ b/src/api/tcpip.c
@@ -313,10 +313,10 @@ tcpip_thread(void *arg)
       break;
 
 #if ETHARP_TCPIP_INPUT || ETHARP_TCPIP_ETHINPUT
-    case TCPIP_MSG_INPUT:
+    case TCPIP_MSG_INPKT:
       LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip_thread: PACKET %p\n", (void *)msg));
 	  msg->msg.inp.f(msg->msg.inp.p, msg->msg.inp.netif);
-	  memp_free(MEMP_TCPIP_MSG_INPUT, msg);
+	  memp_free(MEMP_TCPIP_MSG_INPKT, msg);
       break;
 #endif /* ETHARP_TCPIP_INPUT || ETHARP_TCPIP_ETHINPUT */
 
@@ -330,7 +330,7 @@ tcpip_thread(void *arg)
     case TCPIP_MSG_CALLBACK:
       LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip_thread: CALLBACK %p\n", (void *)msg));
       msg->msg.cb.f(msg->msg.cb.ctx);
-      memp_free(MEMP_TCPIP_MSG, msg);
+      memp_free(MEMP_TCPIP_MSG_API, msg);
       break;
 	case TCPIP_MSG_TIMEOUT:
 	  LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip_thread: TIMEOUT %p\n", (void *)msg));
@@ -339,7 +339,7 @@ tcpip_thread(void *arg)
 		  sys_timeout (msg->msg.tmo.msecs, msg->msg.tmo.h, msg->msg.tmo.arg);
 	  else
 		  sys_untimeout (msg->msg.tmo.h, msg->msg.tmo.arg);
-      memp_free(MEMP_TCPIP_MSG, msg);
+      memp_free(MEMP_TCPIP_MSG_API, msg);
 	  break;
     default:
       break;
@@ -360,12 +360,12 @@ tcpip_input(struct pbuf *p, struct netif *inp)
   struct tcpip_msg *msg;
 
   if (mbox != SYS_MBOX_NULL) {
-    msg = memp_malloc(MEMP_TCPIP_MSG_INPUT);
+    msg = memp_malloc(MEMP_TCPIP_MSG_INPKT);
     if (msg == NULL) {
       return ERR_MEM;
     }
 
-    msg->type = TCPIP_MSG_INPUT;
+    msg->type = TCPIP_MSG_INPKT;
 	msg->msg.inp.f = ip_input;
 	msg->msg.inp.p = p;
 	msg->msg.inp.netif = inp;
@@ -381,12 +381,12 @@ tcpip_input_callback(struct pbuf *p, struct netif *inp, err_t (*f)(struct pbuf *
   struct tcpip_msg *msg;
   
   if (mbox != SYS_MBOX_NULL) {
-	msg = memp_malloc(MEMP_TCPIP_MSG_INPUT);
+	msg = memp_malloc(MEMP_TCPIP_MSG_INPKT);
 	if (msg == NULL) {
 		return ERR_MEM;  
 	}
 
-	msg->type = TCPIP_MSG_INPUT;
+	msg->type = TCPIP_MSG_INPKT;
 	msg->msg.inp.f = f;
     msg->msg.inp.p = p;
     msg->msg.inp.netif = inp;
@@ -427,7 +427,7 @@ tcpip_callback(void (*f)(void *ctx), void *ctx)
   struct tcpip_msg *msg;
 
   if (mbox != SYS_MBOX_NULL) {
-    msg = memp_malloc(MEMP_TCPIP_MSG);
+    msg = memp_malloc(MEMP_TCPIP_MSG_API);
     if (msg == NULL) {
       return ERR_MEM;
     }
@@ -447,7 +447,7 @@ tcpip_timeout(u32_t msecs, sys_timeout_handler h, void *arg)
   struct tcpip_msg *msg;
    
   if (mbox != SYS_MBOX_NULL) {
-	msg = memp_malloc(MEMP_TCPIP_MSG);
+	msg = memp_malloc(MEMP_TCPIP_MSG_API);
 	if (msg == NULL) {
 		return ERR_MEM;  
 	}      
diff --git a/src/core/memp.c b/src/core/memp.c
index fa9f66ff..b70b9d7e 100644
--- a/src/core/memp.c
+++ b/src/core/memp.c
@@ -141,8 +141,8 @@ static const u16_t memp_num[MEMP_MAX] = {
   MEMP_NUM_TCP_SEG,
   MEMP_NUM_NETBUF,
   MEMP_NUM_NETCONN,
-  MEMP_NUM_TCPIP_MSG,
-  MEMP_NUM_TCPIP_MSG_INPUT,
+  MEMP_NUM_TCPIP_MSG_API,
+  MEMP_NUM_TCPIP_MSG_INPKT,
 #if ARP_QUEUEING
   MEMP_NUM_ARP_QUEUE,
 #endif
@@ -168,8 +168,8 @@ static u8_t memp_memory[MEM_ALIGNMENT - 1 +
   MEMP_TYPE_SIZE(MEMP_NUM_TCP_SEG, struct tcp_seg) +
   MEMP_TYPE_SIZE(MEMP_NUM_NETBUF, struct netbuf) +
   MEMP_TYPE_SIZE(MEMP_NUM_NETCONN, struct netconn) +
-  MEMP_TYPE_SIZE(MEMP_NUM_TCPIP_MSG, struct tcpip_msg) +
-  MEMP_TYPE_SIZE(MEMP_NUM_TCPIP_MSG_INPUT, struct tcpip_msg) +
+  MEMP_TYPE_SIZE(MEMP_NUM_TCPIP_MSG_API, struct tcpip_msg) +
+  MEMP_TYPE_SIZE(MEMP_NUM_TCPIP_MSG_INPKT, struct tcpip_msg) +
 #if ARP_QUEUEING
   MEMP_TYPE_SIZE(MEMP_NUM_ARP_QUEUE, struct etharp_q_entry) +
 #endif
diff --git a/src/include/lwip/memp.h b/src/include/lwip/memp.h
index 01078b28..217c5fb8 100644
--- a/src/include/lwip/memp.h
+++ b/src/include/lwip/memp.h
@@ -50,8 +50,8 @@ typedef enum {
 
   MEMP_NETBUF,
   MEMP_NETCONN,
-  MEMP_TCPIP_MSG,
-  MEMP_TCPIP_MSG_INPUT,
+  MEMP_TCPIP_MSG_API,
+  MEMP_TCPIP_MSG_INPKT,
 #if ARP_QUEUEING
   MEMP_ARP_QUEUE,
 #endif
diff --git a/src/include/lwip/opt.h b/src/include/lwip/opt.h
index 54ca863b..eece3241 100644
--- a/src/include/lwip/opt.h
+++ b/src/include/lwip/opt.h
@@ -192,15 +192,22 @@
 #ifndef MEMP_NUM_NETCONN
 #define MEMP_NUM_NETCONN                4
 #endif
-/* MEMP_NUM_TCPIPMSG: the number of struct tcpip_msg, which is used
-   for callback/timeout API communication. Used in src/api/tcpip.c. */
-#ifndef MEMP_NUM_TCPIP_MSG
-#define MEMP_NUM_TCPIP_MSG              8
+
+/* For temporary compatibility with older lwipopts.h */
+#if defined(MEMP_NUM_TCPIP_MSG) && !defined(MEMP_NUM_TCPIP_MSG_API) && !defined(MEMP_NUM_TCPIP_MSG_INPKT)
+#define MEMP_NUM_TCPIP_MSG_API          (MEMP_NUM_TCPIP_MSG / 2)
+#define MEMP_NUM_TCPIP_MSG_INPKT        (MEMP_NUM_TCPIP_MSG)
 #endif
-/* MEMP_NUM_TCPIPMSG_INPUT: the number of struct tcpip_msg, which is used
+
+/* MEMP_NUM_TCPIP_MSG_API: the number of struct tcpip_msg, which is used
+   for callback/timeout API communication. Used in src/api/tcpip.c. */
+#ifndef MEMP_NUM_TCPIP_MSG_API
+#define MEMP_NUM_TCPIP_MSG_API          4
+#endif
+/* MEMP_NUM_TCPIP_MSG_INPKT: the number of struct tcpip_msg, which is used
    for incoming packets. Used in src/api/tcpip.c. */
-#ifndef MEMP_NUM_TCPIP_MSG_INPUT
-#define MEMP_NUM_TCPIP_MSG_INPUT         MEMP_NUM_TCPIP_MSG
+#ifndef MEMP_NUM_TCPIP_MSG_INPKT
+#define MEMP_NUM_TCPIP_MSG_INPKT        8
 #endif
 
 /* ---------- ARP options ---------- */
diff --git a/src/include/lwip/tcpip.h b/src/include/lwip/tcpip.h
index 90de8532..0f373d74 100644
--- a/src/include/lwip/tcpip.h
+++ b/src/include/lwip/tcpip.h
@@ -87,7 +87,7 @@ err_t tcpip_timeout(u32_t msecs, sys_timeout_handler h, void *arg);
 enum tcpip_msg_type {
   TCPIP_MSG_API,
 #if ETHARP_TCPIP_INPUT || ETHARP_TCPIP_ETHINPUT
-  TCPIP_MSG_INPUT,
+  TCPIP_MSG_INPKT,
 #endif /* ETHARP_TCPIP_INPUT || ETHARP_TCPIP_ETHINPUT */
 #if LWIP_NETIF_API
   TCPIP_MSG_NETIFAPI,