diff --git a/Modules.md b/Modules.md
index d87d2d5..3b9f595 100644
--- a/Modules.md
+++ b/Modules.md
@@ -2,7 +2,7 @@
 |Name |Description |
 |-----|------------|
 |amixer |get volume level<br><br> |
-|arch-update |Check updates to Arch Linux.<br> |
+|arch-update |Check updates to Arch Linux.<br><br>Requires the following executable:<br>    * checkupdates (from pacman-contrib)<br> |
 |battery-upower |Displays battery status, remaining percentage and charging information.<br><br>Parameters:<br>    * battery-upower.warning      : Warning threshold in % of remaining charge (defaults to 20)<br>    * battery-upower.critical     : Critical threshold in % of remaining charge (defaults to 10)<br>    * battery-upower.showremaining : If set to true (default) shows the remaining time until the batteries are completely discharged<br> |
 |battery |Displays battery status, remaining percentage and charging information.<br><br>Parameters:<br>    * battery.device     : Comma-separated list of battery devices to read information from (defaults to auto for auto-detection)<br>    * battery.warning    : Warning threshold in % of remaining charge (defaults to 20)<br>    * battery.critical   : Critical threshold in % of remaining charge (defaults to 10)<br>    * battery.showdevice : If set to "true", add the device name to the widget (defaults to False)<br>    * battery.decorate   : If set to "false", hides additional icons (charging, etc.) (defaults to True)<br>    * battery.showpowerconsumption: If set to "true", show current power consumption (defaults to False)<br> |
 |battery_all |Displays battery status, remaining percentage and charging information.<br><br>Parameters:<br>    * battery.device       : Comma-separated list of battery devices to read information from (defaults to auto for auto-detection)<br>    * battery.warning      : Warning threshold in % of remaining charge (defaults to 20)<br>    * battery.critical     : Critical threshold in % of remaining charge (defaults to 10)<br>    * batter.showremaining : If set to true (default) shows the remaining time until the batteries are completely discharged<br> |
diff --git a/bumblebee/modules/arch-update.py b/bumblebee/modules/arch-update.py
index faae680..f0bc70f 100644
--- a/bumblebee/modules/arch-update.py
+++ b/bumblebee/modules/arch-update.py
@@ -1,4 +1,8 @@
 """Check updates to Arch Linux.
+
+Requires the following executable:
+    * checkupdates (from pacman-contrib)
+
 """