diff --git a/sonoff/_changelog.ino b/sonoff/_changelog.ino
index 276084707..874fa5e34 100644
--- a/sonoff/_changelog.ino
+++ b/sonoff/_changelog.ino
@@ -1,4 +1,7 @@
-/* 6.5.0.12 20190521
+/* 6.5.0.13 20190527
+ * Add command SetOption38 6..255 to set IRReceive protocol detection sensitivity mimizing UNKNOWN protocols (#5853)
+ *
+ * 6.5.0.12 20190521
  * Add AriLux RF control GPIO option "ALux IrSel" (159) replacing "Led4i" (59) for full LED control (#5709)
  * Add LED GPIO option "LedLink" (157) and "LedLinki" (158) to select dedicated link status LED (#5709)
  * Add support for up to four LEDs related to four power outputs. Enabled when "LedLink(i)" is configured too (#5709)
diff --git a/sonoff/my_user_config.h b/sonoff/my_user_config.h
index 32b656065..690340c86 100644
--- a/sonoff/my_user_config.h
+++ b/sonoff/my_user_config.h
@@ -417,7 +417,7 @@
   #define USE_IR_RECEIVE                         // Support for IR receiver (+7k2 code, 264 iram)
     #define IR_RCV_BUFFER_SIZE      100          // Max number of packets allowed in capture buffer (default 100 (*2 bytes ram))
     #define IR_RCV_TIMEOUT          15           // Number of milli-Seconds of no-more-data before we consider a message ended (default 15)
-    #define IR_RCV_MIN_UNKNOWN_SIZE 6            // Set the smallest sized "UNKNOWN" message packets we actually care about (default 6)
+    #define IR_RCV_MIN_UNKNOWN_SIZE 6            // Set the smallest sized "UNKNOWN" message packets we actually care about (default 6, max 255)
 
 #define USE_WS2812                               // WS2812 Led string using library NeoPixelBus (+5k code, +1k mem, 232 iram) - Disable by //
   #define USE_WS2812_CTYPE     NEO_GRB           // WS2812 Color type (NEO_RGB, NEO_GRB, NEO_BRG, NEO_RBG, NEO_RGBW, NEO_GRBW)
diff --git a/sonoff/settings.ino b/sonoff/settings.ino
index 7d957ba14..246b503b5 100644
--- a/sonoff/settings.ino
+++ b/sonoff/settings.ino
@@ -813,6 +813,9 @@ void SettingsDefaultSet2(void)
 //  Settings.energy_kWhtotal = 0;
   RtcSettings.energy_kWhtotal = 0;
 
+  // IRRemote
+  Settings.param[P_IR_UNKNOW_THRESHOLD] = IR_RCV_MIN_UNKNOWN_SIZE;
+
   // RF Bridge
 //  for (uint8_t i = 0; i < 17; i++) { Settings.rf_code[i][0] = 0; }
   memcpy_P(Settings.rf_code[0], kDefaultRfCode, 9);
@@ -1168,6 +1171,9 @@ void SettingsDelta(void)
     if (Settings.version < 0x0605000A) {
       Settings.my_adc0 = ADC0_NONE;
     }
+    if (Settings.version < 0x0605000D) {
+      Settings.param[P_IR_UNKNOW_THRESHOLD] = IR_RCV_MIN_UNKNOWN_SIZE;
+    }
 
     Settings.version = VERSION;
     SettingsSave(1);
diff --git a/sonoff/sonoff.h b/sonoff/sonoff.h
index 8be609155..d7d4ef905 100644
--- a/sonoff/sonoff.h
+++ b/sonoff/sonoff.h
@@ -236,7 +236,7 @@ enum ButtonStates { PRESSED, NOT_PRESSED };
 
 enum Shortcuts { SC_CLEAR, SC_DEFAULT, SC_USER };
 
-enum SettingsParmaIndex {P_HOLD_TIME, P_MAX_POWER_RETRY, P_TUYA_DIMMER_ID, P_MDNS_DELAYED_START, P_BOOT_LOOP_OFFSET, P_RGB_REMAP, P_MAX_PARAM8};  // Max is PARAM8_SIZE (18) - SetOption32 until SetOption49
+enum SettingsParmaIndex {P_HOLD_TIME, P_MAX_POWER_RETRY, P_TUYA_DIMMER_ID, P_MDNS_DELAYED_START, P_BOOT_LOOP_OFFSET, P_RGB_REMAP, P_IR_UNKNOW_THRESHOLD, P_MAX_PARAM8};  // Max is PARAM8_SIZE (18) - SetOption32 until SetOption49
 
 enum DomoticzSensors {DZ_TEMP, DZ_TEMP_HUM, DZ_TEMP_HUM_BARO, DZ_POWER_ENERGY, DZ_ILLUMINANCE, DZ_COUNT, DZ_VOLTAGE, DZ_CURRENT, DZ_AIRQUALITY, DZ_MAX_SENSORS};
 
diff --git a/sonoff/sonoff.ino b/sonoff/sonoff.ino
index 48145fb2f..905e8b3ea 100755
--- a/sonoff/sonoff.ino
+++ b/sonoff/sonoff.ino
@@ -851,6 +851,11 @@ void MqttDataHandler(char* topic, uint8_t* data, unsigned int data_len)
               case P_RGB_REMAP:
                 LightUpdateColorMapping();
                 break;
+#ifdef USE_IR_RECEIVE
+              case P_IR_UNKNOW_THRESHOLD:
+                IrReceiveUpdateThreshold();
+                break;
+#endif
             }
           }
         }
diff --git a/sonoff/sonoff_version.h b/sonoff/sonoff_version.h
index e06fab8d0..8b7c27bfc 100644
--- a/sonoff/sonoff_version.h
+++ b/sonoff/sonoff_version.h
@@ -20,6 +20,6 @@
 #ifndef _SONOFF_VERSION_H_
 #define _SONOFF_VERSION_H_
 
-const uint32_t VERSION = 0x0605000C;
+const uint32_t VERSION = 0x0605000D;
 
 #endif  // _SONOFF_VERSION_H_
diff --git a/sonoff/xdrv_05_irremote.ino b/sonoff/xdrv_05_irremote.ino
index 9f1c33a10..9bd0694e3 100644
--- a/sonoff/xdrv_05_irremote.ino
+++ b/sonoff/xdrv_05_irremote.ino
@@ -116,11 +116,17 @@ IRrecv *irrecv = nullptr;
 
 unsigned long ir_lasttime = 0;
 
+void IrReceiveUpdateThreshold()
+{
+  if (Settings.param[P_IR_UNKNOW_THRESHOLD] < 6) { Settings.param[P_IR_UNKNOW_THRESHOLD] = 6; }
+  irrecv->setUnknownThreshold(Settings.param[P_IR_UNKNOW_THRESHOLD]);
+}
+
 void IrReceiveInit(void)
 {
   // an IR led is at GPIO_IRRECV
   irrecv = new IRrecv(pin[GPIO_IRRECV], IR_RCV_BUFFER_SIZE, IR_RCV_TIMEOUT, IR_RCV_SAVE_BUFFER);
-  irrecv->setUnknownThreshold(IR_RCV_MIN_UNKNOWN_SIZE);
+  irrecv->setUnknownThreshold(Settings.param[P_IR_UNKNOW_THRESHOLD]);
   irrecv->enableIRIn();                  // Start the receiver
 
   //  AddLog_P(LOG_LEVEL_DEBUG, PSTR("IrReceive initialized"));