diff --git a/src/_C004.ino b/src/_C004.ino
index 54cbfff56..4583894f8 100644
--- a/src/_C004.ino
+++ b/src/_C004.ino
@@ -124,7 +124,7 @@ bool do_process_c004_delay_queue(int controller_number, const C004_queue_element
   String postStr = do_create_http_request(
     hostName, F("POST"),
     F("/update"), // uri
-    F(""),           // auth_header
+    EMPTY_STRING,           // auth_header
     F("Content-Type: application/x-www-form-urlencoded\r\n"),
     postDataStr.length());
 
diff --git a/src/_C007.ino b/src/_C007.ino
index 3cd69456c..56a1bdab0 100644
--- a/src/_C007.ino
+++ b/src/_C007.ino
@@ -99,13 +99,13 @@ bool do_process_c007_delay_queue(int controller_number, const C007_queue_element
   url += F("&json=");
 
   for (byte i = 0; i < element.valueCount; ++i) {
-    url += (i == 0) ? F("{") : F(",");
+    url += (i == 0) ? '{' : ',';
     url += F("field");
     url += element.idx + i;
-    url += ":";
+    url += ':';
     url += element.txt[i];
   }
-  url += "}";
+  url += '}';
   url += F("&apikey=");
   url += getControllerPass(element.controller_idx, ControllerSettings); // "0UDNN17RW6XAS2E5" // api key
 
diff --git a/src/_C011.ino b/src/_C011.ino
index bd96c3b06..01fe19eeb 100644
--- a/src/_C011.ino
+++ b/src/_C011.ino
@@ -294,8 +294,8 @@ void DeleteNotNeededValues(String& s, byte numberOfValuesWanted)
     if (i < numberOfValuesWanted)
     {
       // yes, so just remove the tokens
-      s.replace(startToken, F(""));
-      s.replace(endToken,  F(""));
+      s.replace(startToken, EMPTY_STRING);
+      s.replace(endToken,  EMPTY_STRING);
     }
     else
     {
@@ -308,7 +308,7 @@ void DeleteNotNeededValues(String& s, byte numberOfValuesWanted)
         String p = s.substring(startIndex, endIndex + 4);
 
         // remove the whole string including tokens
-        s.replace(p, F(""));
+        s.replace(p, EMPTY_STRING);
 
         // find next ones
         startIndex = s.indexOf(startToken);
diff --git a/src/_C015.ino b/src/_C015.ino
index abb7f85ab..f73748acc 100644
--- a/src/_C015.ino
+++ b/src/_C015.ino
@@ -184,7 +184,7 @@ bool CPlugin_015(CPlugin::Function function, struct EventStruct *event, String&
 
           if (!isvalid) {
             // send empty string to Blynk in case of error
-            formattedValue = F("");
+            formattedValue = EMPTY_STRING;
           }
 
           String valueName     = ExtraTaskSettings.TaskDeviceValueNames[x];
diff --git a/src/_N001_Email.ino b/src/_N001_Email.ino
index bc55490f6..e14f1b568 100644
--- a/src/_N001_Email.ino
+++ b/src/_N001_Email.ino
@@ -119,10 +119,10 @@ boolean NPlugin_001_send(const NotificationSettingsStruct& notificationsettings,
 			mailheader.replace(F("$emailfrom"), notificationsettings.Sender);
 		} else {
 			String senderName = email_address.substring(0, pos_less);
-			senderName.replace(F("\""), F("")); // Remove quotes
+			senderName.replace(F("\""), EMPTY_STRING); // Remove quotes
 			String address = email_address.substring(pos_less + 1);
-			address.replace(F("<"), F(""));
-			address.replace(F(">"), F(""));
+			address.replace(F("<"), EMPTY_STRING);
+			address.replace(F(">"), EMPTY_STRING);
 			address.trim();
 			senderName.trim();
 			mailheader.replace(F("$nodename"), senderName);
@@ -139,7 +139,7 @@ boolean NPlugin_001_send(const NotificationSettingsStruct& notificationsettings,
 		// Wait for Client to Start Sending
 		// The MTA Exchange
 		while (true) {
-			if (!NPlugin_001_MTA(client, F(""), F("220 "))) break;
+			if (!NPlugin_001_MTA(client, EMPTY_STRING, F("220 "))) break;
 			if (!NPlugin_001_MTA(client, String(F("EHLO ")) + notificationsettings.Domain, F("250 "))) break;
 			if (!NPlugin_001_Auth(client, notificationsettings.User, notificationsettings.Pass)) break;
 			if (!NPlugin_001_MTA(client, String(F("MAIL FROM:<")) + notificationsettings.Sender + ">", F("250 "))) break;
diff --git a/src/_P022_PCA9685.ino b/src/_P022_PCA9685.ino
index e733e1e07..ca0fb1267 100644
--- a/src/_P022_PCA9685.ino
+++ b/src/_P022_PCA9685.ino
@@ -193,8 +193,8 @@ boolean Plugin_022(byte function, struct EventStruct *event, String& string)
       {
         LoadTaskSettings(event->TaskIndex);
         String name = line.substring(0, dotPos);
-        name.replace(F("["), F(""));
-        name.replace(F("]"), F(""));
+        name.replace(F("["), EMPTY_STRING);
+        name.replace(F("]"), EMPTY_STRING);
 
         if (name.equalsIgnoreCase(getTaskDeviceName(event->TaskIndex))) {
           line            = line.substring(dotPos + 1);
diff --git a/src/_P050_TCS34725.ino b/src/_P050_TCS34725.ino
index 9b0523f7e..d913a4736 100644
--- a/src/_P050_TCS34725.ino
+++ b/src/_P050_TCS34725.ino
@@ -417,7 +417,7 @@ boolean Plugin_050(byte function, struct EventStruct *event, String& string)
                 RuleEvent += String((float)b / t * sRGBFactor, 4);
                 break;
               default:
-                RuleEvent = F("");
+                RuleEvent = EMPTY_STRING;
                 break;
               }
               if (RuleEvent.length() != 0) {
@@ -453,7 +453,7 @@ boolean Plugin_050(byte function, struct EventStruct *event, String& string)
               RuleEvent += c;
               break;
             default:
-              RuleEvent = F("");
+              RuleEvent = EMPTY_STRING;
               break;
             }
             if (RuleEvent.length() != 0) {
diff --git a/src/_P062_MPR121_KeyPad.ino b/src/_P062_MPR121_KeyPad.ino
index 19366c496..bdc24147f 100644
--- a/src/_P062_MPR121_KeyPad.ino
+++ b/src/_P062_MPR121_KeyPad.ino
@@ -120,8 +120,8 @@ boolean Plugin_062(byte function, struct EventStruct *event, String& string)
         }
         P062_data->loadTouchObjects(event->TaskIndex);
 
-        addRowLabel(F("Object"), F(""));
-        html_table(F(""), false);  // Sub-table
+        addRowLabel(F("Object"));
+        html_table(EMPTY_STRING, false);  // Sub-table
         html_table_header(F("&nbsp;#&nbsp;"));
         html_table_header(F("Touch (0..255)"));
         html_table_header(F("Release (0..255)"));
diff --git a/src/_P073_7DGT.ino b/src/_P073_7DGT.ino
index 241399fa0..37c6c7065 100644
--- a/src/_P073_7DGT.ino
+++ b/src/_P073_7DGT.ino
@@ -94,7 +94,7 @@ struct P073_data_struct : public PluginTaskData_base {
     #endif // P073_7DBIN_COMMAND
     #ifdef P073_SCROLL_TEXT
     , txtScrolling(false), scrollCount(0), scrollPos(0), scrollFull(false)
-    , _scrollSpeed(0), _textToScroll(F(""))
+    , _scrollSpeed(0)
     #endif // P073_SCROLL_TEXT
      {
     ClearBuffer();
@@ -353,7 +353,7 @@ struct P073_data_struct : public PluginTaskData_base {
   }
 
   void setTextToScroll(const String& text) {
-    _textToScroll = F("");
+    _textToScroll = EMPTY_STRING;
     if (text.length() > 0) {
       int bufToFill = getBufferLength(displayModel);
       _textToScroll.reserve(text.length() + bufToFill + (scrollFull ? bufToFill : 0));
@@ -1473,7 +1473,7 @@ bool p073_plugin_write_7dbin(struct EventStruct *event, const String& text) {
     #endif // P073_SCROLL_TEXT
     if (data.length() > 0) {
       #ifdef P073_SCROLL_TEXT
-      P073_data->setTextToScroll(F("")); // Clear any scrolling text
+      P073_data->setTextToScroll(EMPTY_STRING); // Clear any scrolling text
       if (P073_data->txtScrolling && data.length() > bufLen) {
         P073_data->setBinaryData(data);
       } else
diff --git a/src/_P079_Wemos_Motorshield.ino b/src/_P079_Wemos_Motorshield.ino
index c4e4a7ded..157b99af5 100644
--- a/src/_P079_Wemos_Motorshield.ino
+++ b/src/_P079_Wemos_Motorshield.ino
@@ -178,7 +178,7 @@ boolean Plugin_079(byte function, struct EventStruct *event, String& string)
       }
 
 
-      if (getTaskDeviceName(event->TaskIndex) == F("")) {                    // Check to see if user entered device name.
+      if (getTaskDeviceName(event->TaskIndex).length() == 0) {                    // Check to see if user entered device name.
         switch (Plugin_079_MotorShield_type) {
           case P079_BoardType::WemosMotorshield:
             safe_strncpy(ExtraTaskSettings.TaskDeviceName, F(PLUGIN_DEF_NAME1_079), sizeof(ExtraTaskSettings.TaskDeviceName)); // Name missing, populate default name.
diff --git a/src/_P081_Cron.ino b/src/_P081_Cron.ino
index c873a358f..e8a2062e9 100644
--- a/src/_P081_Cron.ino
+++ b/src/_P081_Cron.ino
@@ -225,7 +225,7 @@ boolean Plugin_081(byte function, struct EventStruct *event, String& string)
         log = SaveCustomTaskSettings(event->TaskIndex, (byte *)&expression_c, PLUGIN_081_EXPRESSION_SIZE);
       }
 
-      if (log != F(""))
+      if (log.length() > 0)
       {
         addLog(LOG_LEVEL_ERROR, String(PSTR(PLUGIN_NAME_081)) + F(": Saving ") + log);
       }
diff --git a/src/_P087_SerialProxy.ino b/src/_P087_SerialProxy.ino
index 4562af89d..016d94f1d 100644
--- a/src/_P087_SerialProxy.ino
+++ b/src/_P087_SerialProxy.ino
@@ -331,17 +331,17 @@ void P087_html_show_matchForms(struct EventStruct *event) {
         case 1:
         {
           // Comparator
-          String options[2];
+          const __FlashStringHelper * options[2];
           options[P087_Filter_Comp::Equal]    = F("==");
           options[P087_Filter_Comp::NotEqual] = F("!=");
           int optionValues[2] = { P087_Filter_Comp::Equal, P087_Filter_Comp::NotEqual };
-          addSelector(id, 2, options, optionValues, NULL, comparator, false, F(""));
+          addSelector(id, 2, options, optionValues, NULL, comparator, false, EMPTY_STRING);
           break;
         }
         case 2:
         {
           // Compare with
-          addTextBox(id, filter, 32, false, false, F(""), F(""));
+          addTextBox(id, filter, 32, false, false, EMPTY_STRING, EMPTY_STRING);
           break;
         }
       }
diff --git a/src/_P093_MitsubishiHP.ino b/src/_P093_MitsubishiHP.ino
index 5af80c7f8..268b2677e 100644
--- a/src/_P093_MitsubishiHP.ino
+++ b/src/_P093_MitsubishiHP.ino
@@ -655,7 +655,7 @@ private:
 
   static void dumpPacket(const uint8_t* packet, size_t length, String& result) {
     for (size_t idx = 0; idx < length; ++idx) {
-      result += formatToHex(packet[idx], F(""));
+      result += formatToHex(packet[idx], EMPTY_STRING);
       result += ' ';
     }
   }
diff --git a/src/_P094_CULReader.ino b/src/_P094_CULReader.ino
index 13e384e9d..e3b9ebfb4 100644
--- a/src/_P094_CULReader.ino
+++ b/src/_P094_CULReader.ino
@@ -405,7 +405,7 @@ void P094_html_show_matchForms(struct EventStruct *event) {
                 options[i]      = P094_data_struct::P094_FilterValueType_toString(filterValueType);
                 optionValues[i] = filterValueType;
               }
-              addSelector(id, P094_FILTER_VALUE_Type_NR_ELEMENTS, options, optionValues, NULL, capture, false, true, F(""));
+              addSelector(id, P094_FILTER_VALUE_Type_NR_ELEMENTS, options, optionValues, NULL, capture, false, true, EMPTY_STRING);
             }
 
             break;
@@ -427,13 +427,13 @@ void P094_html_show_matchForms(struct EventStruct *event) {
               options[i]      = P094_data_struct::P094_FilterComp_toString(enumValue);
               optionValues[i] = enumValue;
             }
-            addSelector(id, P094_FILTER_COMP_NR_ELEMENTS, options, optionValues, NULL, comparator, false, true, F(""));
+            addSelector(id, P094_FILTER_COMP_NR_ELEMENTS, options, optionValues, NULL, comparator, false, true, EMPTY_STRING);
             break;
           }
           case 3:
           {
             // Compare with
-            addTextBox(id, filter, 8, false, false, F(""), F(""));
+            addTextBox(id, filter, 8, false, false, EMPTY_STRING, EMPTY_STRING);
             break;
           }
         }
diff --git a/src/_P095_ILI9341.ino b/src/_P095_ILI9341.ino
index e682e0546..bf6a4b359 100644
--- a/src/_P095_ILI9341.ino
+++ b/src/_P095_ILI9341.ino
@@ -276,8 +276,8 @@ boolean Plugin_095(byte function, struct EventStruct *event, String& string)
         String tmpString = String(string);
         String arguments = String(string);
 
-        String command = F("");
-        String subcommand = F("");
+        String command;
+        String subcommand;
 
         int argIndex = arguments.indexOf(',');
         if (argIndex)
diff --git a/src/_P096_eInk.ino b/src/_P096_eInk.ino
index 7210164fc..bb55c2f9d 100644
--- a/src/_P096_eInk.ino
+++ b/src/_P096_eInk.ino
@@ -300,8 +300,8 @@ boolean Plugin_096(byte function, struct EventStruct *event, String& string)
 #endif
         String arguments = String(string);
 
-        String command = F("");
-        String subcommand = F("");
+        String command;
+        String subcommand;
 
         int argIndex = arguments.indexOf(',');
         if (argIndex)
diff --git a/src/_P099_XPT2046Touch.ino b/src/_P099_XPT2046Touch.ino
index a78d5bb3f..5bfb8850e 100644
--- a/src/_P099_XPT2046Touch.ino
+++ b/src/_P099_XPT2046Touch.ino
@@ -211,8 +211,8 @@ boolean Plugin_099(byte function, struct EventStruct *event, String& string)
         }
         if (tbUseCalibration) {
 
-          addRowLabel(F("Calibration"), F(""));
-          html_table(F(""), false);  // Sub-table
+          addRowLabel(F("Calibration"));
+          html_table(EMPTY_STRING, false);  // Sub-table
           html_table_header(F(""));
           html_table_header(F("x"));
           html_table_header(F("y"));
@@ -256,8 +256,8 @@ boolean Plugin_099(byte function, struct EventStruct *event, String& string)
         }
         if (P099_CONFIG_OBJECTCOUNT > -1) {
 
-          addRowLabel(F("Object"), F(""));
-          html_table(F(""), false);  // Sub-table
+          addRowLabel(F("Object"));
+          html_table(EMPTY_STRING, false);  // Sub-table
           html_table_header(F("&nbsp;#&nbsp;"));
           html_table_header(F("Objectname"));
           html_table_header(F("Top-left x"));
@@ -275,7 +275,7 @@ boolean Plugin_099(byte function, struct EventStruct *event, String& string)
             addTextBox(getPluginCustomArgName(objectNr),
                       String(P099_data->StoredSettings.TouchObjects[objectNr].objectname),
                       P099_MaxObjectNameLength - 1,
-                      false, false, F(""), F(""));
+                      false, false, EMPTY_STRING, EMPTY_STRING);
             html_TD();
             addNumericBox(getPluginCustomArgName(objectNr + 100), P099_data->StoredSettings.TouchObjects[objectNr].top_left.x,     0, 65535);
             html_TD();
@@ -420,9 +420,9 @@ boolean Plugin_099(byte function, struct EventStruct *event, String& string)
 
     case PLUGIN_WRITE:
     {
-      String command = F("");
-      String subcommand = F("");
-      String arguments = F("");
+      String command;
+      String subcommand;
+      String arguments;
       arguments.reserve(24);
 
       int argIndex = string.indexOf(',');
diff --git a/src/_P112_AS7265x.ino b/src/_P112_AS7265x.ino
index 82f666b28..9de8926aa 100644
--- a/src/_P112_AS7265x.ino
+++ b/src/_P112_AS7265x.ino
@@ -146,7 +146,7 @@ boolean Plugin_112(byte function, struct EventStruct *event, String& string)
         optionValuesMode3[1] = AS7265X_INDICATOR_CURRENT_LIMIT_2MA;
         optionValuesMode3[2] = AS7265X_INDICATOR_CURRENT_LIMIT_4MA;
         optionValuesMode3[3] = AS7265X_INDICATOR_CURRENT_LIMIT_8MA;
-        addFormSelector(F(""), F("p112_BlueStatusLEDCurrentLimit"), 4, optionsMode3, optionValuesMode3, choiceMode3);
+        addFormSelector(EMPTY_STRING, F("p112_BlueStatusLEDCurrentLimit"), 4, optionsMode3, optionValuesMode3, choiceMode3);
       }
       addHtml(F(" Current Limit"));
       addFormNote(F("Activate Status LEDs only for debugging purpose."));
diff --git a/src/_Plugin_Helper.cpp b/src/_Plugin_Helper.cpp
index f6cb8dace..abfbf43a1 100644
--- a/src/_Plugin_Helper.cpp
+++ b/src/_Plugin_Helper.cpp
@@ -96,7 +96,7 @@ void pluginWebformShowValue(taskIndex_t taskIndex, byte varNr, const String& lab
 }
 
 void pluginWebformShowValue(const String& valName, const String& value, bool addBR) {
-  pluginWebformShowValue(valName, F(""), value, F(""), addBR);
+  pluginWebformShowValue(valName, EMPTY_STRING, value, EMPTY_STRING, addBR);
 }
 
 void pluginWebformShowValue(const String& valName, const String& valName_id, const String& value, const String& value_id, bool addBR) {
diff --git a/src/src/DataStructs/Web_StreamingBuffer.cpp b/src/src/DataStructs/Web_StreamingBuffer.cpp
index cc0a469d4..dadaaec3e 100644
--- a/src/src/DataStructs/Web_StreamingBuffer.cpp
+++ b/src/src/DataStructs/Web_StreamingBuffer.cpp
@@ -122,7 +122,7 @@ void Web_StreamingBuffer::checkFull(void) {
 }
 
 void Web_StreamingBuffer::startStream() {
-  startStream(false, F(""));
+  startStream(false, EMPTY_STRING);
 }
 
 void Web_StreamingBuffer::startStream(const String& origin) {
@@ -261,7 +261,7 @@ void Web_StreamingBuffer::sendHeaderBlocking(bool json, const String& origin) {
   if (json) {
     web_server.sendHeader(F("Access-Control-Allow-Origin"), "*");
   }
-  web_server.send(200, json ? F("application/json") : F("text/html"), F(""));
+  web_server.send(200, json ? F("application/json") : F("text/html"), EMPTY_STRING);
 #else // if defined(ESP8266) && defined(ARDUINO_ESP8266_RELEASE_2_3_0)
   unsigned int timeout          = 0;
   const uint32_t freeBeforeSend = ESP.getFreeHeap();
@@ -276,7 +276,7 @@ void Web_StreamingBuffer::sendHeaderBlocking(bool json, const String& origin) {
   if (origin.length() > 0) {
     web_server.sendHeader(F("Access-Control-Allow-Origin"), origin);
   }
-  web_server.send(200, json ? F("application/json") : F("text/html"), F(""));
+  web_server.send(200, json ? F("application/json") : F("text/html"), EMPTY_STRING);
 
   // dont wait on 2.3.0. Memory returns just too slow.
   while ((ESP.getFreeHeap() < freeBeforeSend) &&
diff --git a/src/src/ESPEasyCore/ESPEasyRules.cpp b/src/src/ESPEasyCore/ESPEasyRules.cpp
index d3dbac239..eb0c1f05e 100644
--- a/src/src/ESPEasyCore/ESPEasyRules.cpp
+++ b/src/src/ESPEasyCore/ESPEasyRules.cpp
@@ -171,7 +171,7 @@ void rulesProcessing(const String& event) {
  \*********************************************************************************************/
 String rulesProcessingFile(const String& fileName, const String& event) {
   if (!Settings.UseRules || !fileExists(fileName)) {
-    return F("");
+    return EMPTY_STRING;
   }
   #ifndef BUILD_NO_RAM_TRACKER
   checkRAM(F("rulesProcessingFile"));
@@ -192,7 +192,7 @@ String rulesProcessingFile(const String& fileName, const String& event) {
   if (nestingLevel > RULES_MAX_NESTING_LEVEL) {
     addLog(LOG_LEVEL_ERROR, F("EVENT: Error: Nesting level exceeded!"));
     nestingLevel--;
-    return F("");
+    return EMPTY_STRING;
   }
 
   fs::File f = tryOpenFile(fileName, "r+");
@@ -252,7 +252,7 @@ String rulesProcessingFile(const String& fileName, const String& event) {
           }
 
           // Prepare for new line
-          line = F("");
+          line = EMPTY_STRING;
           line.reserve(longestLineSize);
           firstNonSpaceRead = false;
           commentFound      = false;
@@ -302,7 +302,7 @@ String rulesProcessingFile(const String& fileName, const String& event) {
   #ifndef BUILD_NO_RAM_TRACKER
   checkRAM(F("rulesProcessingFile2"));
   #endif // ifndef BUILD_NO_RAM_TRACKER
-  return F("");
+  return EMPTY_STRING;
 }
 
 /********************************************************************************************\
@@ -737,7 +737,7 @@ void parseCompleteNonCommentLine(String& line, const String& event,
 
   String eventTrigger;
 
-  action = F("");
+  action = EMPTY_STRING;
 
   if (!codeBlock) // do not check "on" rules if a block of actions is to be
                   // processed
@@ -948,8 +948,8 @@ bool ruleMatch(const String& event, const String& rule) {
   tmpRule.trim();
 
   // Ignore escape char
-  tmpRule.replace(F("["), F(""));
-  tmpRule.replace(F("]"), F(""));
+  tmpRule.replace(F("["), EMPTY_STRING);
+  tmpRule.replace(F("]"), EMPTY_STRING);
 
   if (tmpEvent.equalsIgnoreCase(tmpRule)) {
     return true;
diff --git a/src/src/Globals/Plugins.cpp b/src/src/Globals/Plugins.cpp
index 01917daa2..1a45f51b0 100644
--- a/src/src/Globals/Plugins.cpp
+++ b/src/src/Globals/Plugins.cpp
@@ -412,8 +412,8 @@ bool PluginCall(byte Function, struct EventStruct *event, String& str)
         dotPos = arg0.indexOf('.');
         if (dotPos > -1) {
           String thisTaskName = command.substring(0, dotPos); // Extract taskname prefix
-          thisTaskName.replace(F("["), F(""));                      // Remove the optional square brackets
-          thisTaskName.replace(F("]"), F(""));
+          thisTaskName.replace(F("["), EMPTY_STRING);                      // Remove the optional square brackets
+          thisTaskName.replace(F("]"), EMPTY_STRING);
           if (thisTaskName.length() > 0) {                    // Second precondition
             taskIndex_t thisTask = findTaskIndexByName(thisTaskName);
             if (!validTaskIndex(thisTask)) {                  // Taskname not found or invalid, check for a task number?
diff --git a/src/src/Helpers/Dallas1WireHelper.cpp b/src/src/Helpers/Dallas1WireHelper.cpp
index b4d033900..c3080e777 100644
--- a/src/src/Helpers/Dallas1WireHelper.cpp
+++ b/src/src/Helpers/Dallas1WireHelper.cpp
@@ -154,7 +154,7 @@ void Dallas_addr_selector_webform_load(taskIndex_t TaskIndex, int8_t gpio_pin_rx
     }
     addRowLabel(rowLabel);
     addSelector_Head(id);
-    addSelector_Item(F("- None -"), -1, false, false, F("")); // Empty choice
+    addSelector_Item(F("- None -"), -1, false, false, EMPTY_STRING); // Empty choice
     uint8_t tmpAddress[8];
 
     // get currently saved address
@@ -171,7 +171,7 @@ void Dallas_addr_selector_webform_load(taskIndex_t TaskIndex, int8_t gpio_pin_rx
       }
 
       bool selected = (memcmp(tmpAddress, savedAddress, 8) == 0) ? true : false;
-      addSelector_Item(option, index, selected, false, F(""));
+      addSelector_Item(option, index, selected, false, EMPTY_STRING);
     }
     addSelector_Foot();
   }
diff --git a/src/src/Helpers/Networking.cpp b/src/src/Helpers/Networking.cpp
index 92a716a57..41601ad78 100644
--- a/src/src/Helpers/Networking.cpp
+++ b/src/src/Helpers/Networking.cpp
@@ -350,7 +350,7 @@ String formatUnitToIPAddress(byte unit, byte formatCode) {
     switch (formatCode) {
       case 1:                  // Return empty string
       {
-        return F("");
+        return EMPTY_STRING;
       }
       case 2: // Return "0"
       {
@@ -1166,7 +1166,7 @@ String splitURL(const String& fullURL, String& host, uint16_t& port, String& fil
 bool downloadFile(const String& url, String file_save) {
   String error;
 
-  return downloadFile(url, file_save, F(""), F(""), error);
+  return downloadFile(url, file_save, EMPTY_STRING, EMPTY_STRING, error);
 }
 
 bool downloadFile(const String& url, String file_save, const String& user, const String& pass, String& error) {
diff --git a/src/src/Helpers/StringConverter.cpp b/src/src/Helpers/StringConverter.cpp
index 437cac41e..38e1497ec 100644
--- a/src/src/Helpers/StringConverter.cpp
+++ b/src/src/Helpers/StringConverter.cpp
@@ -167,7 +167,7 @@ String formatToHex(unsigned long value) {
 String formatHumanReadable(unsigned long value, unsigned long factor) {
   String result = formatHumanReadable(value, factor, 2);
 
-  result.replace(F(".00"), F(""));
+  result.replace(F(".00"), EMPTY_STRING);
   return result;
 }
 
@@ -216,7 +216,7 @@ String formatToHex_decimal(unsigned long value, unsigned long factor) {
   return result;
 }
 
-String boolToString(bool value) {
+const __FlashStringHelper * boolToString(bool value) {
   return value ? F("true") : F("false");
 }
 
@@ -224,7 +224,7 @@ String boolToString(bool value) {
    Typical string replace functions.
 \*********************************************************************************************/
 void removeExtraNewLine(String& line) {
-  while (line.endsWith("\r\n\r\n")) {
+  while (line.endsWith(F("\r\n\r\n"))) {
     line.remove(line.length() - 2);
   }
 }
@@ -237,7 +237,7 @@ void addNewLine(String& line) {
    Format a value to the set number of decimals
 \*********************************************************************************************/
 String doFormatUserVar(struct EventStruct *event, byte rel_index, bool mustCheck, bool& isvalid) {
-  if (event == nullptr) return F("");
+  if (event == nullptr) return EMPTY_STRING;
   isvalid = true;
 
   const deviceIndex_t DeviceIndex = getDeviceIndex_from_TaskIndex(event->TaskIndex);
@@ -278,7 +278,7 @@ String doFormatUserVar(struct EventStruct *event, byte rel_index, bool mustCheck
       addLog(LOG_LEVEL_ERROR, log);
     }
     #endif // ifndef BUILD_NO_DEBUG
-    return F("");
+    return EMPTY_STRING;
   }
 
   switch (sensorType) {
@@ -522,7 +522,7 @@ String parseStringKeepCase(const String& string, byte indexFind, char separator)
   String result;
 
   if (!GetArgv(string.c_str(), result, indexFind, separator)) {
-    return F("");
+    return EMPTY_STRING;
   }
   result.trim();
   return stripQuotes(result);
@@ -558,7 +558,7 @@ String parseStringToEndKeepCase(const String& string, byte indexFind, char separ
   }
 
   if (!hasArgument || (pos_begin < 0)) {
-    return F("");
+    return EMPTY_STRING;
   }
   String result = string.substring(pos_begin, pos_end);
 
@@ -575,7 +575,7 @@ String tolerantParseStringKeepCase(const String& string, byte indexFind, char se
 }
 
 // escapes special characters in strings for use in html-forms
-bool htmlEscapeChar(char c, String& escaped)
+bool htmlEscapeChar(char c, const __FlashStringHelper * escaped)
 {
   switch (c)
   {
@@ -591,10 +591,10 @@ bool htmlEscapeChar(char c, String& escaped)
 
 void htmlEscape(String& html, char c)
 {
-  String repl;
+  const __FlashStringHelper * repl = F("");
 
   if (htmlEscapeChar(c, repl)) {
-    html.replace(String(c), repl);
+    html.replace(String(c), String(repl));
   }
 }
 
@@ -784,7 +784,7 @@ void parseSingleControllerVariable(String            & s,
     LoadTaskSettings(event->TaskIndex);
     repl(F("%valname%"), ExtraTaskSettings.TaskDeviceValueNames[taskValueIndex], s, useURLencode);
   } else {
-    repl(F("%valname%"), F(""), s, useURLencode);
+    repl(F("%valname%"), EMPTY_STRING, s, useURLencode);
   }
 }
 
@@ -825,7 +825,7 @@ void parseEventVariables(String& s, struct EventStruct *event, bool useURLencode
     LoadTaskSettings(event->TaskIndex);
     repl(F("%tskname%"), ExtraTaskSettings.TaskDeviceName, s, useURLencode);
   } else {
-    repl(F("%tskname%"), F(""), s, useURLencode);
+    repl(F("%tskname%"), EMPTY_STRING, s, useURLencode);
   }
 
   const bool vname_found = s.indexOf(F("%vname")) != -1;
@@ -839,7 +839,7 @@ void parseEventVariables(String& s, struct EventStruct *event, bool useURLencode
       if (validTaskIndex(event->TaskIndex)) {
         repl(vname, ExtraTaskSettings.TaskDeviceValueNames[i], s, useURLencode);
       } else {
-        repl(vname, F(""), s, useURLencode);
+        repl(vname, EMPTY_STRING, s, useURLencode);
       }
     }
   }
@@ -950,7 +950,7 @@ void parseStandardConversions(String& s, bool useURLencode) {
   SMART_CONV(F("%c_m2dh%"),   minutesToDayHour(data.arg1))
   SMART_CONV(F("%c_m2dhm%"),  minutesToDayHourMinute(data.arg1))
   SMART_CONV(F("%c_s2dhms%"), secondsToDayHourMinuteSecond(data.arg1))
-  SMART_CONV(F("%c_2hex%"),   formatToHex(data.arg1, F("")))
+  SMART_CONV(F("%c_2hex%"),   formatToHex(data.arg1, EMPTY_STRING))
   #undef SMART_CONV
 
   // Conversions with 2 parameters
diff --git a/src/src/Helpers/StringConverter.h b/src/src/Helpers/StringConverter.h
index 6393d44a4..d4d69cc62 100644
--- a/src/src/Helpers/StringConverter.h
+++ b/src/src/Helpers/StringConverter.h
@@ -78,7 +78,7 @@ String formatToHex_decimal(unsigned long value);
 String formatToHex_decimal(unsigned long value,
                            unsigned long factor);
 
-String boolToString(bool value);
+const __FlashStringHelper * boolToString(bool value);
 
 /*********************************************************************************************\
    Typical string replace functions.
@@ -190,7 +190,7 @@ String tolerantParseStringKeepCase(const String& string,
 
 // escapes special characters in strings for use in html-forms
 bool   htmlEscapeChar(char    c,
-                      String& escaped);
+                      const __FlashStringHelper * escaped);
 
 void   htmlEscape(String& html,
                   char    c);
diff --git a/src/src/Helpers/StringProvider.h b/src/src/Helpers/StringProvider.h
index 5f51f0140..f2edfb598 100644
--- a/src/src/Helpers/StringProvider.h
+++ b/src/src/Helpers/StringProvider.h
@@ -3,6 +3,9 @@
 
 #include "../../ESPEasy_common.h"
 
+
+
+
 struct LabelType;
 
 // enum LabelType::Enum : short;
diff --git a/src/src/Helpers/_CPlugin_DomoticzHelper.cpp b/src/src/Helpers/_CPlugin_DomoticzHelper.cpp
index e6894abc1..075a417f8 100644
--- a/src/src/Helpers/_CPlugin_DomoticzHelper.cpp
+++ b/src/src/Helpers/_CPlugin_DomoticzHelper.cpp
@@ -254,7 +254,7 @@ String serializeDomoticzJson(struct EventStruct *event)
     json += to_json_object_value(F("RSSI"), String(mapRSSItoDomoticz()));
     #  if FEATURE_ADC_VCC
     json += ',';
-    json += to_json_object_value(F("Battery"), mapVccToDomoticz());
+    json += to_json_object_value(F("Battery"), String(mapVccToDomoticz()));
     #  endif // if FEATURE_ADC_VCC
 
     const Sensor_VType sensorType = event->getSensorType();
diff --git a/src/src/Helpers/_CPlugin_Helper.cpp b/src/src/Helpers/_CPlugin_Helper.cpp
index b3b2e5294..b0872e08a 100644
--- a/src/src/Helpers/_CPlugin_Helper.cpp
+++ b/src/src/Helpers/_CPlugin_Helper.cpp
@@ -197,8 +197,8 @@ String do_create_http_request(
   const String& hostportString,
   const String& method, const String& uri) {
   return do_create_http_request(hostportString, method, uri,
-                                F(""), // auth_header
-                                F(""), // additional_options
+                                EMPTY_STRING, // auth_header
+                                EMPTY_STRING, // additional_options
                                 -1  // content_length
                                 );
 }
@@ -213,8 +213,8 @@ String do_create_http_request(
     defaultport ? ControllerSettings.getHost() : ControllerSettings.getHostPortString(),
     method,
     uri,
-    F(""), // auth_header
-    F(""), // additional_options
+    EMPTY_STRING, // auth_header
+    EMPTY_STRING, // additional_options
     content_length);
 }
 
@@ -229,7 +229,7 @@ String create_http_request_auth(
     method,
     uri,
     get_auth_header(controller_index, ControllerSettings),
-    F(""), // additional_options
+    EMPTY_STRING, // additional_options
     content_length);
 }
 
diff --git a/src/src/Helpers/_CPlugin_Helper_webform.cpp b/src/src/Helpers/_CPlugin_Helper_webform.cpp
index acc9da5db..d6d963bc4 100644
--- a/src/src/Helpers/_CPlugin_Helper_webform.cpp
+++ b/src/src/Helpers/_CPlugin_Helper_webform.cpp
@@ -83,7 +83,7 @@ String getControllerParameterName(protocolIndex_t                   ProtocolInde
   if (!displayName) {
     // Change name to lower case and remove spaces to make it an internal name.
     name.toLowerCase();
-    name.replace(F(" "), F(""));
+    name.replace(F(" "), EMPTY_STRING);
   }
   return name;
 }
diff --git a/src/src/Helpers/_Plugin_Helper_serial.cpp b/src/src/Helpers/_Plugin_Helper_serial.cpp
index 5e0d97879..951be2e89 100644
--- a/src/src/Helpers/_Plugin_Helper_serial.cpp
+++ b/src/src/Helpers/_Plugin_Helper_serial.cpp
@@ -113,7 +113,7 @@ void serialHelper_addI2CuartSelectors(int address, int channel) {
   {
     String id = F("i2cuart_addr");
     addRowLabel_tr_id(F("I2C Address"), id);
-    do_addSelector_Head(id, F(""), F(""), false);
+    do_addSelector_Head(id, EMPTY_STRING, EMPTY_STRING, false);
 
     if ((address < SC16IS752_I2C_BASE_ADDR) || (address >= (SC16IS752_I2C_BASE_ADDR + SC16IS752_I2C_ADDRESSES))) {
       // selected address is not in range
@@ -129,7 +129,7 @@ void serialHelper_addI2CuartSelectors(int address, int channel) {
       option += F(" (datasheet: ");
       option += formatToHex(addr * 2);
       option += ')';
-      addSelector_Item(option, addr, addr == address, false, F(""));
+      addSelector_Item(option, addr, addr == address, false, EMPTY_STRING);
     }
     addSelector_Foot();
   }
@@ -307,7 +307,7 @@ void serialHelper_serialconfig_webformLoad(struct EventStruct *event, byte curre
   String id = F("serConf");
 
   addRowLabel_tr_id(F("Serial Config"), id);
-  do_addSelector_Head(id, F(""), F(""), false);
+  do_addSelector_Head(id, EMPTY_STRING, EMPTY_STRING, false);
 
   if (currentSelection == 0) {
     // Must truncate it to 1 byte, since ESP32 uses a 32-bit value. We add these high bits later for ESP32.
@@ -336,7 +336,7 @@ void serialHelper_serialconfig_webformLoad(struct EventStruct *event, byte curre
           case 1:  value += 0x10; break;
           case 2:  value += 0x30; break;
         }
-        addSelector_Item(label, value, value == currentSelection, false, F(""));
+        addSelector_Item(label, value, value == currentSelection, false, EMPTY_STRING);
       }
     }
   }
diff --git a/src/src/PluginStructs/P094_data_struct.cpp b/src/src/PluginStructs/P094_data_struct.cpp
index 3f0aa8926..c37378104 100644
--- a/src/src/PluginStructs/P094_data_struct.cpp
+++ b/src/src/PluginStructs/P094_data_struct.cpp
@@ -3,10 +3,9 @@
 // Needed also here for PlatformIO's library finder as the .h file 
 // is in a directory which is excluded in the src_filter
 #include <ESPeasySerial.h>
-#include <Regexp.h>
-
 
 #ifdef USES_P094
+#include <Regexp.h>
 
 #include "../Globals/ESPEasy_time.h"
 #include "../Helpers/StringConverter.h"
diff --git a/src/src/WebServer/ControllerPage.cpp b/src/src/WebServer/ControllerPage.cpp
index 85992e189..f8adadb8a 100644
--- a/src/src/WebServer/ControllerPage.cpp
+++ b/src/src/WebServer/ControllerPage.cpp
@@ -191,8 +191,8 @@ void handle_controllers_ShowAllControllersTable()
 {
   html_table_class_multirow();
   html_TR();
-  html_table_header(F(""),           70);
-  html_table_header(F("Nr"),         50);
+  html_table_header(F(""),        70);
+  html_table_header(F("Nr"),      50);
   html_table_header(F("Enabled"), 100);
   html_table_header(F("Protocol"));
   html_table_header(F("Host"));
@@ -277,7 +277,7 @@ void handle_controllers_ControllerSettingsPage(controllerIndex_t controllerindex
   addRowLabel(F("Protocol"));
   byte choice = Settings.Protocol[controllerindex];
   addSelector_Head_reloadOnChange(F("protocol"));
-  addSelector_Item(F("- Standalone -"), 0, false, false, F(""));
+  addSelector_Item(F("- Standalone -"), 0, false, false, EMPTY_STRING);
 
   for (byte x = 0; x <= protocolCount; x++)
   {
diff --git a/src/src/WebServer/CustomPage.cpp b/src/src/WebServer/CustomPage.cpp
index 9e111cd62..e0173533c 100644
--- a/src/src/WebServer/CustomPage.cpp
+++ b/src/src/WebServer/CustomPage.cpp
@@ -97,7 +97,7 @@ boolean handle_custom(String path) {
         else {
           name += Settings.Name;
         }
-        addSelector_Item(name, it->first, choice == it->first, false, F(""));
+        addSelector_Item(name, it->first, choice == it->first, false, EMPTY_STRING);
       }
     }
     addSelector_Foot();
diff --git a/src/src/WebServer/DevicesPage.cpp b/src/src/WebServer/DevicesPage.cpp
index c56dcf6fb..1aec95853 100644
--- a/src/src/WebServer/DevicesPage.cpp
+++ b/src/src/WebServer/DevicesPage.cpp
@@ -199,7 +199,7 @@ void addDeviceSelect(const String& name,  int choice)
   String deviceName;
 
   addSelector_Head_reloadOnChange(name);
-  addSelector_Item(F("- None -"), 0, false, false, F(""));
+  addSelector_Item(F("- None -"), 0, false, false, EMPTY_STRING);
 
   for (byte x = 0; x <= deviceCount; x++)
   {
@@ -1104,8 +1104,8 @@ void devicePage_show_I2C_config(taskIndex_t taskIndex)
     }
 
     if (multipleMuxPorts) {
-      addRowLabel(F("Select connections"), F(""));
-      html_table(F(""), false); // Sub-table
+      addRowLabel(F("Select connections"), EMPTY_STRING);
+      html_table(EMPTY_STRING, false); // Sub-table
       html_table_header(F("Channel"));
       html_table_header(F("Enable"));
       html_table_header(F("Channel"));
diff --git a/src/src/WebServer/HTML_wrappers.cpp b/src/src/WebServer/HTML_wrappers.cpp
index 133d279bf..352240d13 100644
--- a/src/src/WebServer/HTML_wrappers.cpp
+++ b/src/src/WebServer/HTML_wrappers.cpp
@@ -153,7 +153,7 @@ void html_table_header(const __FlashStringHelper * label, int width) {
 }
 
 void html_table_header(const String& label, int width) {
-  html_table_header(label, F(""), F(""), width);
+  html_table_header(label, EMPTY_STRING, EMPTY_STRING, width);
 }
 
 void html_table_header(const __FlashStringHelper * label, const __FlashStringHelper * helpButton, int width) {
@@ -161,15 +161,15 @@ void html_table_header(const __FlashStringHelper * label, const __FlashStringHel
 }
 
 void html_table_header(const String& label, const __FlashStringHelper * helpButton, int width) {
-  html_table_header(label, helpButton, F(""), width);
+  html_table_header(label, helpButton, EMPTY_STRING, width);
 }
 
 void html_table_header(const __FlashStringHelper * label, const String& helpButton, int width) {
-  html_table_header(label, helpButton, F(""), width);
+  html_table_header(label, helpButton, EMPTY_STRING, width);
 }
 
 void html_table_header(const String& label, const String& helpButton, int width) {
-  html_table_header(label, helpButton, F(""), width);
+  html_table_header(label, helpButton, EMPTY_STRING, width);
 }
 
 void html_table_header(const __FlashStringHelper * label, const __FlashStringHelper * helpButton, const String& rtdHelpButton, int width) {
@@ -226,7 +226,7 @@ void html_end_form() {
 }
 
 void html_add_button_prefix() {
-  html_add_button_prefix(F(""), true);
+  html_add_button_prefix(EMPTY_STRING, true);
 }
 
 void html_add_button_prefix(const String& classes, bool enabled) {
@@ -249,7 +249,7 @@ void html_add_button_prefix(const String& classes, bool enabled) {
 }
 
 void html_add_wide_button_prefix() {
-  html_add_wide_button_prefix(F(""), true);
+  html_add_wide_button_prefix(EMPTY_STRING, true);
 }
 
 void html_add_wide_button_prefix(const String& classes, bool enabled) {
@@ -397,11 +397,11 @@ void addHtmlLink(const String& htmlclass, const String& url, const String& label
 }
 
 void addHtmlDiv(const String& htmlclass) {
-  addHtmlDiv(htmlclass, F(""));
+  addHtmlDiv(htmlclass, EMPTY_STRING);
 }
 
 void addHtmlDiv(const String& htmlclass, const String& content) {
-  addHtmlDiv(htmlclass, content, F(""));
+  addHtmlDiv(htmlclass, content, EMPTY_STRING);
 }
 
 void addHtmlDiv(const String& htmlclass, const String& content, const String& id) {
diff --git a/src/src/WebServer/Log.cpp b/src/src/WebServer/Log.cpp
index 7820fb5d0..748cfe8fb 100644
--- a/src/src/WebServer/Log.cpp
+++ b/src/src/WebServer/Log.cpp
@@ -27,7 +27,7 @@ void handle_log() {
 
   #ifdef WEBSERVER_LOG
   addHtml(F("<TR><TH id=\"headline\" align=\"left\">Log"));
-  addCopyButton(F("copyText"), F(""), F("Copy log to clipboard"));
+  addCopyButton(F("copyText"), EMPTY_STRING, F("Copy log to clipboard"));
   addHtml(F("</TR></table><div  id='current_loglevel' style='font-weight: bold;'>Logging: </div><div class='logviewer' id='copyText_1'></div>"));
   addHtml(F("Autoscroll: "));
   addCheckBox(F("autoscroll"), true);
diff --git a/src/src/WebServer/Markup.cpp b/src/src/WebServer/Markup.cpp
index a084f9b80..dbae3c55c 100644
--- a/src/src/WebServer/Markup.cpp
+++ b/src/src/WebServer/Markup.cpp
@@ -72,7 +72,7 @@ void addSelector(const String& id,
   {
     addSelector_Head_reloadOnChange(id, classname, !enabled);
   } else {
-    do_addSelector_Head(id, classname, F(""), !enabled);
+    do_addSelector_Head(id, classname, EMPTY_STRING, !enabled);
   }
   addSelector_options(optionCount, options, indices, attr, selectedIndex);
   addSelector_Foot();
@@ -93,7 +93,7 @@ void addSelector(const String& id,
   {
     addSelector_Head_reloadOnChange(id, classname, !enabled);
   } else {
-    do_addSelector_Head(id, classname, F(""), !enabled);
+    do_addSelector_Head(id, classname, EMPTY_STRING, !enabled);
   }
   addSelector_options(optionCount, options, indices, attr, selectedIndex);
   addSelector_Foot();
@@ -144,7 +144,7 @@ void addSelector_options(int optionCount, const String options[], const int indi
 }
 
 void addSelector_Head(const String& id) {
-  do_addSelector_Head(id, F("wide"), F(""), false);
+  do_addSelector_Head(id, F("wide"), EMPTY_STRING, false);
 }
 
 void addSelector_Head_reloadOnChange(const String& id) {
@@ -363,12 +363,12 @@ void addTableSeparator(const String& label, int colspan, int h_size, const Strin
 
 void addFormHeader(const __FlashStringHelper * header) {
   html_TR();
-  html_table_header(header, F(""), F(""), 225);
+  html_table_header(header, EMPTY_STRING, EMPTY_STRING, 225);
   html_table_header(F(""));
 }
 
 void addFormHeader(const String& header, const String& helpButton) {
-  addFormHeader(header, helpButton, F(""));
+  addFormHeader(header, helpButton, EMPTY_STRING);
 }
 
 void addFormHeader(const String& header, const String& helpButton, const String& rtdHelpButton)
diff --git a/src/src/WebServer/Markup_Buttons.cpp b/src/src/WebServer/Markup_Buttons.cpp
index eda5104f2..ab4e871ac 100644
--- a/src/src/WebServer/Markup_Buttons.cpp
+++ b/src/src/WebServer/Markup_Buttons.cpp
@@ -7,7 +7,7 @@
 
 
 void addButton(const __FlashStringHelper * url, const __FlashStringHelper * label) {
-  addButton(url, label, F(""));
+  addButton(url, label, EMPTY_STRING);
 }
 
 void addButton(const __FlashStringHelper * url, const __FlashStringHelper * label, const __FlashStringHelper * classes, bool enabled)
@@ -21,7 +21,7 @@ void addButton(const __FlashStringHelper * url, const __FlashStringHelper * labe
 
 void addButton(const String& url, const String& label)
 {
-  addButton(url, label, F(""));
+  addButton(url, label, EMPTY_STRING);
 }
 
 void addButton(const String& url, const String& label, const String& classes, bool enabled)
@@ -35,7 +35,7 @@ void addButton(const String& url, const String& label, const String& classes, bo
 
 void addButtonWithSvg(const String& url, const String& label)
 {
-  addButtonWithSvg(url, label, F(""), false);
+  addButtonWithSvg(url, label, EMPTY_STRING, false);
 }
 
 void addButtonWithSvg(const String& url, const String& label, const String& svgPath, bool needConfirm) {
@@ -74,7 +74,7 @@ void addSaveButton(const String& url, const String& label)
 {
 #ifdef BUILD_MINIMAL_OTA
   addButtonWithSvg(url, label
-                   , F("")
+                   , EMPTY_STRING
                    , false);
 #else // ifdef BUILD_MINIMAL_OTA
   addButtonWithSvg(url,
@@ -91,7 +91,7 @@ void addDeleteButton(const String& url, const String& label)
 {
 #ifdef BUILD_MINIMAL_OTA
   addButtonWithSvg(url, label
-                   , F("")
+                   , EMPTY_STRING
                    , true);
 #else // ifdef BUILD_MINIMAL_OTA
   addButtonWithSvg(url,
@@ -105,7 +105,7 @@ void addDeleteButton(const String& url, const String& label)
 }
 
 void addWideButton(const __FlashStringHelper * url, const __FlashStringHelper * label) {
-  html_add_wide_button_prefix(F(""), true);
+  html_add_wide_button_prefix(EMPTY_STRING, true);
   addHtml(url);
   addHtml("'>");
   addHtml(label);
@@ -113,7 +113,7 @@ void addWideButton(const __FlashStringHelper * url, const __FlashStringHelper *
 }
 
 void addWideButton(const String& url, const String& label) {
-  addWideButton(url, label, F(""), true);
+  addWideButton(url, label, EMPTY_STRING, true);
 }
 
 void addWideButton(const String& url, const String& label, const String& classes) {
@@ -141,7 +141,7 @@ void addSubmitButton(const __FlashStringHelper * value, const __FlashStringHelpe
 }
 
 void addSubmitButton(const String& value, const String& name) {
-  addSubmitButton(value, name, F(""));
+  addSubmitButton(value, name, EMPTY_STRING);
 }
 
 void addSubmitButton(const __FlashStringHelper * value, const __FlashStringHelper * name, const __FlashStringHelper * classes)
diff --git a/src/src/WebServer/Markup_Forms.cpp b/src/src/WebServer/Markup_Forms.cpp
index ce2eedd70..da6f32265 100644
--- a/src/src/WebServer/Markup_Forms.cpp
+++ b/src/src/WebServer/Markup_Forms.cpp
@@ -31,7 +31,7 @@ void addFormSeparator(int clspan)
 // ********************************************************************************
 void addFormNote(const __FlashStringHelper * text)
 {
-  addRowLabel_tr_id(F(""), F(""));
+  addRowLabel_tr_id(EMPTY_STRING, EMPTY_STRING);
   addHtml(F(" <div "));
   addHtmlAttribute(F("class"), F("note"));
   addHtml('>');
@@ -42,7 +42,7 @@ void addFormNote(const __FlashStringHelper * text)
 
 void addFormNote(const String& text, const String& id)
 {
-  addRowLabel_tr_id(F(""), id);
+  addRowLabel_tr_id(EMPTY_STRING, id);
   addHtmlDiv(F("note"), String(F("Note: ")) + text);
 }
 
@@ -177,7 +177,7 @@ void addFormIPBox(const String& label, const String& id, const byte ip[4])
   addHtmlAttribute(F("class"), F("wide"));
   addHtmlAttribute(F("type"),  F("text"));
   addHtmlAttribute(F("name"),  id);
-  addHtmlAttribute(F("value"), (empty_IP) ? F("") : formatIP(ip));
+  addHtmlAttribute(F("value"), (empty_IP) ? EMPTY_STRING : formatIP(ip));
   addHtml('>');
 }
 
@@ -209,7 +209,7 @@ void addFormPinSelectI2C(const String& label, const String& id, int choice)
 void addFormSelectorI2C(const String& id, int addressCount, const int addresses[], int selectedIndex)
 {
   addRowLabel_tr_id(F("I2C Address"), id);
-  do_addSelector_Head(id, F(""), F(""), false);
+  do_addSelector_Head(id, EMPTY_STRING, EMPTY_STRING, false);
 
   for (byte x = 0; x < addressCount; x++)
   {
@@ -218,7 +218,7 @@ void addFormSelectorI2C(const String& id, int addressCount, const int addresses[
     if (x == 0) {
       option += F(" - (default)");
     }
-    addSelector_Item(option, addresses[x], addresses[x] == selectedIndex, false, F(""));
+    addSelector_Item(option, addresses[x], addresses[x] == selectedIndex, false, EMPTY_STRING);
   }
   addSelector_Foot();
 }
@@ -291,7 +291,7 @@ void addFormSelector_script(const String& label,
                             const String& onChangeCall)
 {
   addRowLabel_tr_id(label, id);
-  do_addSelector_Head(id, F(""), onChangeCall, false);
+  do_addSelector_Head(id, EMPTY_STRING, onChangeCall, false);
   addSelector_options(optionCount, options, indices, attr, selectedIndex);
   addSelector_Foot();
 }
diff --git a/src/src/WebServer/NotificationPage.cpp b/src/src/WebServer/NotificationPage.cpp
index b3d9c9ade..d3810ddbe 100644
--- a/src/src/WebServer/NotificationPage.cpp
+++ b/src/src/WebServer/NotificationPage.cpp
@@ -157,7 +157,7 @@ void handle_notifications() {
     addRowLabel(F("Notification"));
     byte choice = Settings.Notification[notificationindex];
     addSelector_Head_reloadOnChange(F("notification"));
-    addSelector_Item(F("- None -"), 0, false, false, F(""));
+    addSelector_Item(F("- None -"), 0, false, false, EMPTY_STRING);
 
     for (byte x = 0; x <= notificationCount; x++)
     {
diff --git a/src/src/WebServer/Rules.cpp b/src/src/WebServer/Rules.cpp
index 8e3b64b1f..b13ac8b1d 100644
--- a/src/src/WebServer/Rules.cpp
+++ b/src/src/WebServer/Rules.cpp
@@ -91,7 +91,7 @@ void handle_rules() {
   html_TR_TD();
   html_end_form();
   addHtml(F("<button id='save_button' class='button' onClick='saveRulesFile()'>Save</button>"));
-  addHtmlDiv(F(""), F("Saved!"), F("toastmessage"));
+  addHtmlDiv(EMPTY_STRING, F("Saved!"), F("toastmessage"));
 
   addButton(fileName, F("Download to file"));
   html_end_table();
@@ -356,7 +356,7 @@ void handle_rules_delete() {
   if (removed)
   {
     web_server.sendHeader(F("Location"), F("/rules"), true);
-    web_server.send(302, F("text/plain"), F(""));
+    web_server.send(302, F("text/plain"), EMPTY_STRING);
   }
   else
   {
@@ -472,7 +472,7 @@ bool handle_rules_edit(String originalUri, bool isAddNew) {
 
         if (isAddNew) {
           web_server.sendHeader(F("Location"), F("/rules"), true);
-          web_server.send(302, F("text/plain"), F(""));
+          web_server.send(302, F("text/plain"), EMPTY_STRING);
           return true;
         }
       }
@@ -594,7 +594,7 @@ bool Rule_Download(const String& path)
 
 void Goto_Rules_Root() {
   web_server.sendHeader(F("Location"), F("/rules"), true);
-  web_server.send(302, F("text/plain"), F(""));
+  web_server.send(302, F("text/plain"), EMPTY_STRING);
 }
 
 bool EnumerateFileAndDirectory(String          & rootPath
diff --git a/src/src/WebServer/SetupPage.cpp b/src/src/WebServer/SetupPage.cpp
index d0555e374..6ecd4f658 100644
--- a/src/src/WebServer/SetupPage.cpp
+++ b/src/src/WebServer/SetupPage.cpp
@@ -359,7 +359,7 @@ void handle_setup_scan_and_show(const String& ssid, const String& other, const S
   html_TR_TD();
   html_TD();
   html_BR();
-  addSubmitButton(F("Connect"), F(""));
+  addSubmitButton(F("Connect"), EMPTY_STRING);
 
   html_end_table();
 }
diff --git a/src/src/WebServer/ToolsPage.cpp b/src/src/WebServer/ToolsPage.cpp
index cc863330e..7bbd5f6a3 100644
--- a/src/src/WebServer/ToolsPage.cpp
+++ b/src/src/WebServer/ToolsPage.cpp
@@ -134,7 +134,7 @@ void handle_tools() {
       bool     otaEnabled = OTA_possible(maxSketchSize, use2step);
       addFormSubHeader(F("Firmware"));
       html_TR_TD_height(30);
-      addWideButton(F("update"), F("Update Firmware"), F(""), otaEnabled);
+      addWideButton(F("update"), F("Update Firmware"), EMPTY_STRING, otaEnabled);
       addHelpButton(F("EasyOTA"));
       html_TD();
       addHtml(F("Load a new firmware "));
diff --git a/src/src/WebServer/WebServer.cpp b/src/src/WebServer/WebServer.cpp
index 2e320ec4d..e99722a15 100644
--- a/src/src/WebServer/WebServer.cpp
+++ b/src/src/WebServer/WebServer.cpp
@@ -234,12 +234,12 @@ size_t streamFile_htmlEscape(const String& fileName)
 
   if (f)
   {
-    String escaped;
-
     while (f.available())
     {
       char c = (char)f.read();
 
+      const __FlashStringHelper * escaped = F("");
+
       if (htmlEscapeChar(c, escaped)) {
         addHtml(escaped);
       } else {
@@ -268,7 +268,7 @@ bool captivePortal() {
     }
     #endif
     web_server.sendHeader(F("Location"), redirectURL, true);
-    web_server.send(302, F("text/plain"), F(""));   // Empty content inhibits Content-length header so we have to close the socket ourselves.
+    web_server.send(302, F("text/plain"), EMPTY_STRING);   // Empty content inhibits Content-length header so we have to close the socket ourselves.
     web_server.client().stop(); // Stop is needed because we sent no content length
     return true;
   }