diff --git a/homeassistant/components/knx.py b/homeassistant/components/knx.py
index d7630fee7a5..f6f41619ca8 100644
--- a/homeassistant/components/knx.py
+++ b/homeassistant/components/knx.py
@@ -17,7 +17,7 @@ import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.event import async_track_state_change
 from homeassistant.helpers.script import Script
 
-REQUIREMENTS = ['xknx==0.8.3']
+REQUIREMENTS = ['xknx==0.8.4']
 
 DOMAIN = "knx"
 DATA_KNX = "data_knx"
diff --git a/homeassistant/components/light/knx.py b/homeassistant/components/light/knx.py
index 1b14ff75ecc..83083e34bad 100644
--- a/homeassistant/components/light/knx.py
+++ b/homeassistant/components/light/knx.py
@@ -109,8 +109,8 @@ class KNXLight(Light):
     @property
     def brightness(self):
         """Return the brightness of this light between 0..255."""
-        return self.device.brightness \
-            if self.device.supports_dimming else \
+        return self.device.current_brightness \
+            if self.device.supports_brightness else \
             None
 
     @property
@@ -122,7 +122,7 @@ class KNXLight(Light):
     def rgb_color(self):
         """Return the RBG color value."""
         if self.device.supports_color:
-            return self.device.current_color()
+            return self.device.current_color
         return None
 
     @property
@@ -154,7 +154,7 @@ class KNXLight(Light):
     def supported_features(self):
         """Flag supported features."""
         flags = 0
-        if self.device.supports_dimming:
+        if self.device.supports_brightness:
             flags |= SUPPORT_BRIGHTNESS
         if self.device.supports_color:
             flags |= SUPPORT_RGB_COLOR
@@ -162,10 +162,12 @@ class KNXLight(Light):
 
     async def async_turn_on(self, **kwargs):
         """Turn the light on."""
-        if ATTR_BRIGHTNESS in kwargs and self.device.supports_dimming:
-            await self.device.set_brightness(int(kwargs[ATTR_BRIGHTNESS]))
+        if ATTR_BRIGHTNESS in kwargs:
+            if self.device.supports_brightness:
+                await self.device.set_brightness(int(kwargs[ATTR_BRIGHTNESS]))
         elif ATTR_RGB_COLOR in kwargs:
-            await self.device.set_color(kwargs[ATTR_RGB_COLOR])
+            if self.device.supports_color:
+                await self.device.set_color(kwargs[ATTR_RGB_COLOR])
         else:
             await self.device.set_on()
 
diff --git a/requirements_all.txt b/requirements_all.txt
index e8bf58a61a9..09ada578e5e 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -1268,7 +1268,7 @@ xbee-helper==0.0.7
 xboxapi==0.1.1
 
 # homeassistant.components.knx
-xknx==0.8.3
+xknx==0.8.4
 
 # homeassistant.components.media_player.bluesound
 # homeassistant.components.sensor.startca