diff --git a/sonoff/support.ino b/sonoff/support.ino
index 035a1d31d..b9fec8651 100644
--- a/sonoff/support.ino
+++ b/sonoff/support.ino
@@ -124,6 +124,18 @@ size_t strcspn(const char *str1, const char *str2)
   return ret;
 }
 
+// https://clc-wiki.net/wiki/C_standard_library:string.h:strpbrk
+// Locate the first occurrence in the string pointed to by s1 of any character from the string pointed to by s2
+char* strpbrk(const char *s1, const char *s2)
+{
+  while(*s1) {
+    if (strchr(s2, *s1++)) {
+      return (char*)--s1;
+    }
+  }
+  return 0;
+}
+
 // https://opensource.apple.com/source/Libc/Libc-583/stdlib/FreeBSD/strtoull.c
 // Convert a string to an unsigned long long integer
 #ifndef __LONG_LONG_MAX__
diff --git a/sonoff/xdrv_10_rules.ino b/sonoff/xdrv_10_rules.ino
index d46900e5a..26bdbcb86 100644
--- a/sonoff/xdrv_10_rules.ino
+++ b/sonoff/xdrv_10_rules.ino
@@ -887,7 +887,7 @@ char * findClosureBracket(char * pStart)
   if (bFindClosures) {
     return pointer;
   } else {
-    return NULL;
+    return nullptr;
   }
 }
 
@@ -1015,7 +1015,7 @@ bool findNextObjectValue(char * &pointer, float &value)
       break;
     } else if (*pointer == '(') {     //It is a sub expression bracketed with ()
       char * closureBracket = findClosureBracket(pointer);        //Get the position of closure bracket ")"
-      if (closureBracket != NULL) {
+      if (closureBracket != nullptr) {
         value = evaluateExpression(pointer+1, closureBracket - pointer - 2);
         pointer = closureBracket + 1;
         bSucceed = true;
@@ -1310,7 +1310,7 @@ bool findNextLogicObjectValue(char * &pointer, bool &value)
       break;
     } else if (*pointer == '(') {     //It is a sub expression bracketed with ()
       char * closureBracket = findClosureBracket(pointer);        //Get the position of closure bracket ")"
-      if (closureBracket != NULL) {
+      if (closureBracket != nullptr) {
         value = evaluateLogicalExpression(pointer+1, closureBracket - pointer - 2);
         pointer = closureBracket + 1;
         bSucceed = true;
@@ -1555,7 +1555,7 @@ void ProcessIfStatement(const char* statements)
     while (*pos && *pos != '(') {
       pos++;
     }
-    if (NULL == *pos) break;
+    if (0 == *pos) { break; }
     char * posEnd = findClosureBracket(pos);
 
     if (true == evaluateLogicalExpression(pos + 1, posEnd - (pos + 1))) {