installation-instructions.md

@@ -82,7 +82,7 @@ to install it.
 For [Debian](http://www.debian.org/) or [Ubuntu](http://www.ubuntu.com/), add the following lines to your `/etc/apt/sources.list`,
 
 ```
-deb http://downloads.skewed.de/apt DISTRIBUTION main
+deb [ arch=amd64 ] https://downloads.skewed.de/apt DISTRIBUTION main
 ```
 where `DISTRIBUTION` can be any one of