diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8903e69..67795e8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -299,4 +299,4 @@
 ## 3.3.6
 * The fix in 3.3.4 for tile naming in Home app was not supported with HomeBridge. Add setting of Name property back for HomeBridge compatibility. 
 * Fix issue with threshold triggers and WeatherUnderground. In 3.3.4, WeatherUnderground API call was modified and incorrectly return values in km, and km/h. 
-* Fix punycode deprication warning.
+* Fix punycode deprication warning and util._extend warning.
diff --git a/package.json b/package.json
index 71ace0a..f4e6604 100644
--- a/package.json
+++ b/package.json
@@ -114,7 +114,6 @@
     "fakegato-history": "^0.6.4",
     "geo-tz": "^6.0.0",
     "moment-timezone": "^0.5.28",
-    "underscore": "^1.13.6",
     "request": "^2.88.2",
     "weather-formulas": "^1",
     "node-persist": "^2.1.0",
diff --git a/util/characteristics.js b/util/characteristics.js
index 9f0587d..03f0488 100644
--- a/util/characteristics.js
+++ b/util/characteristics.js
@@ -1,7 +1,5 @@
 /* jshint asi: true, esversion: 6, laxbreak: true, laxcomma: true, node: true, undef: true, unused: true */
 
-const underscore = require('underscore');
-
 const inherits = require('util').inherits,
 	CustomUUID = {
 		// Eve UUID
@@ -69,7 +67,7 @@ module.exports = function (Characteristic, units)
 		var range = (units !== 'imperial') ? {unit: 'mm', maxValue: max, minValue: 0, minStep: 0.1}
 			: {unit: 'in', maxValue: Math.round(max / 25.4), minValue: 0, minStep: 0.01};
 
-		return underscore.extend(
+		return Object.assign(
 			{
 				format: Characteristic.Formats.FLOAT
 				, perms: [Characteristic.Perms.READ, Characteristic.Perms.NOTIFY]
@@ -90,7 +88,7 @@ module.exports = function (Characteristic, units)
 						minValue: temperatureValue(min),
 						maxValue: temperatureValue(max)};
 
-		return underscore.extend(
+		return Object.assign(
 			{
 				format: Characteristic.Formats.FLOAT
 				, minStep: 0.1
@@ -107,7 +105,7 @@ module.exports = function (Characteristic, units)
 		var range = ((units === 'si') || (units === 'sitorr') || (units === 'ca')) ? {unit: 'km', maxValue: max, minValue: 0}
 			: {unit: 'mi', maxValue: km2mi(max), minValue: 0};
 
-		return underscore.extend(
+		return Object.assign(
 			{
 				format: Characteristic.Formats.UINT8
 				, minStep: 1
@@ -133,7 +131,7 @@ module.exports = function (Characteristic, units)
 			: (units === 'ca') ? {unit: 'km/h', maxValue: mtos2kmh(max), minValue: 0}
 				: {unit: 'mph', maxValue: mtos2mih(max), minValue: 0};
 
-		return underscore.extend(
+		return Object.assign(
 			{
 				format: Characteristic.Formats.UINT8
 				, minStep: 0.1
@@ -156,7 +154,7 @@ module.exports = function (Characteristic, units)
 		let range = (units === 'sitorr') ? {unit: 'mmhg', maxValue: hpa2mmhg(max), minValue: hpa2mmhg(min)}
 			: {unit: 'hPa', maxValue: max, minValue: min};
 
-		return underscore.extend(
+		return Object.assign(
 			{
 				format: Characteristic.Formats.UINT16
 				, minStep: 1