README: urge users to use a release

README.md

@@ -6,6 +6,15 @@ If you're new to Gluon and ready to get your feet wet, have a look at the
 
 **Gluon IRC channel: `#gluon` in [hackint](http://hackint.org/)**
 
+## Use a release!
+
+Please refrain from using the master branch for anything else but development purposes!
+Use the most recent release instead. You can list all relaseses by running `git branch -a`
+and switch to one by running `git checkout v2014.3;make update`.
+
+If you're using the autoupdater, do not autoupdate nodes with anything but releases.
+If you upgrade using random master commits the nodes *will break* eventually.
+
 ## Mailinglist (mostly for announcements)
 
 I can handle administrative requests automatically. Please