diff --git a/src/api/tcpip.c b/src/api/tcpip.c
index 2d4fbab2..2c85b9f9 100644
--- a/src/api/tcpip.c
+++ b/src/api/tcpip.c
@@ -566,7 +566,7 @@ pbuf_free_int(void *p)
 err_t
 pbuf_free_callback(struct pbuf *p)
 {
-  return tcpip_callback_with_block(pbuf_free_int, p, 0);
+  return tcpip_try_callback(pbuf_free_int, p);
 }
 
 /**
@@ -579,7 +579,7 @@ pbuf_free_callback(struct pbuf *p)
 err_t
 mem_free_callback(void *m)
 {
-  return tcpip_callback_with_block(mem_free, m, 0);
+  return tcpip_try_callback(mem_free, m);
 }
 
 #endif /* !NO_SYS */
diff --git a/src/core/netif.c b/src/core/netif.c
index 880d7454..b77d1071 100644
--- a/src/core/netif.c
+++ b/src/core/netif.c
@@ -1000,7 +1000,7 @@ netif_loop_output(struct netif *netif, struct pbuf *p)
 
 #if LWIP_NETIF_LOOPBACK_MULTITHREADING
   /* For multithreading environment, schedule a call to netif_poll */
-  tcpip_callback_with_block((tcpip_callback_fn)netif_poll, netif, 0);
+  tcpip_try_callback((tcpip_callback_fn)netif_poll, netif);
 #endif /* LWIP_NETIF_LOOPBACK_MULTITHREADING */
 
   return ERR_OK;
diff --git a/src/core/pbuf.c b/src/core/pbuf.c
index 93f7da99..102bbe47 100644
--- a/src/core/pbuf.c
+++ b/src/core/pbuf.c
@@ -99,7 +99,7 @@
 #ifndef PBUF_POOL_FREE_OOSEQ_QUEUE_CALL
 #include "lwip/tcpip.h"
 #define PBUF_POOL_FREE_OOSEQ_QUEUE_CALL()  do { \
-  if (tcpip_callback_with_block(pbuf_free_ooseq_callback, NULL, 0) != ERR_OK) { \
+  if (tcpip_try_callback(pbuf_free_ooseq_callback, NULL) != ERR_OK) { \
       SYS_ARCH_PROTECT(old_level); \
       pbuf_free_ooseq_pending = 0; \
       SYS_ARCH_UNPROTECT(old_level); \
diff --git a/src/include/lwip/apps/smtp.h b/src/include/lwip/apps/smtp.h
index 8b0db581..a7cfeba8 100644
--- a/src/include/lwip/apps/smtp.h
+++ b/src/include/lwip/apps/smtp.h
@@ -40,7 +40,7 @@ typedef void (*smtp_result_fn)(void *arg, u8_t smtp_result, u16_t srv_err, err_t
  * which in turn can be used with tcpip_callback() to send mail
  * from interrupt context, e.g. like this:
  *    struct smtp_send_request *req; (to be filled)
- *    tcpip_callback_with_block(smtp_send_mail_int, (void*)req, 0);
+ *    tcpip_try_callback(smtp_send_mail_int, (void*)req);
  *
  * For member description, see parameter description of smtp_send_mail().
  * When using with tcpip_callback, this structure has to stay allocated
diff --git a/src/netif/ppp/pppos.c b/src/netif/ppp/pppos.c
index fb48df4e..7bf40f21 100644
--- a/src/netif/ppp/pppos.c
+++ b/src/netif/ppp/pppos.c
@@ -544,7 +544,7 @@ pppos_input(ppp_pcb *ppp, u8_t *s, int l)
           pbuf_header(inp, -(s16_t)(PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN));
 #endif /* IP_FORWARD || LWIP_IPV6_FORWARD */
 #if PPP_INPROC_IRQ_SAFE
-          if(tcpip_callback_with_block(pppos_input_callback, inp, 0) != ERR_OK) {
+          if(tcpip_try_callback(pppos_input_callback, inp) != ERR_OK) {
             PPPDEBUG(LOG_ERR, ("pppos_input[%d]: tcpip_callback() failed, dropping packet\n", ppp->netif->num));
             pbuf_free(inp);
             LINK_STATS_INC(link.drop);