diff --git a/docs/ReleaseNotes.md b/docs/ReleaseNotes.md
index 30d03c1..64b0184 100644
--- a/docs/ReleaseNotes.md
+++ b/docs/ReleaseNotes.md
@@ -5,6 +5,9 @@
 
 # Homebridge MQTT-Thing: Release Notes
 
+### Version 1.1.39
++ Fix RGB light validation errors (issue #510)
+
 ### Version 1.1.38
 + Fix to use valid initial value for airPressure (0 invalid)
 
diff --git a/index.js b/index.js
index 621e007..c5919f5 100644
--- a/index.js
+++ b/index.js
@@ -975,9 +975,9 @@ function makeThing( log, accessoryConfig, api ) {
                     blue = Math.min( blue + white, 255 );
 
                     var hsv = RGBtoScaledHSV( red, green, blue );
-                    var hue = hsv.h;
-                    var sat = hsv.s;
-                    var bri = hsv.v;
+                    var hue = Math.floor( hsv.h );
+                    var sat = Math.floor( hsv.s );
+                    var bri = Math.floor( hsv.v );
 
                     if( !config.topics.setOn ) {
                         var on = bri > 0 ? 1 : 0;
diff --git a/package.json b/package.json
index ca06f5a..1844fc6 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "homebridge-mqttthing",
-  "version": "1.1.38",
+  "version": "1.1.39",
   "description": "Homebridge plugin supporting various services over MQTT",
   "main": "index.js",
   "scripts": {
diff --git a/test/backups/instance-backups/homebridge-backup-DB7DA324AA69.1642526521547.tar.gz b/test/backups/instance-backups/homebridge-backup-DB7DA324AA69.1642526521547.tar.gz
new file mode 100644
index 0000000..f719686
Binary files /dev/null and b/test/backups/instance-backups/homebridge-backup-DB7DA324AA69.1642526521547.tar.gz differ
diff --git a/test/config.json b/test/config.json
index 14c7f3a..ea08bed 100644
--- a/test/config.json
+++ b/test/config.json
@@ -997,6 +997,33 @@
                 "xsetRotationSpeed": "test/fan/setRotationSpeed"
             },
             "integerValue": true
+        }, {
+            "accessory": "mqttthing",
+            "type": "lightbulb-OnOff",
+            "name": "Toggle-Light",
+            "url": "homebridge2",
+            "logMqtt": true,
+            "topics": {
+                "getOn": "test/toggleLight/getOn",
+                "setOn": {
+                    "topic": "test/toggleLight/setOn",
+                    "apply": "return 1;"
+                }
+            },
+            "integerValue": true
+        }, {
+            "accessory": "mqttthing",
+            "type": "lightbulb",
+            "url": "homebridge2",
+            "topics": {
+                "getOn": "test/DimmerRgb1",
+                "setOn": "test/DimmerRgb1",
+                "getRGB": "test/DimmerRgb1/rgb",
+                "setRGB": "test/DimmerRgb1/rgb"
+            },
+            "onValue": "on",
+            "offValue": "off",
+            "name": "RGBTest"
         }
     ]
 }