diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml
index 3bc5d3c66f6..c3c9561f2fb 100644
--- a/man/systemd.unit.xml
+++ b/man/systemd.unit.xml
@@ -189,6 +189,11 @@
                 respectively. The prefix name here refers to the
                 string before the @, i.e. "getty" in the example
                 above, where "tty3" is the instance name.</para>
+
+                <para>The unit file format is covered by the
+                <ulink
+                url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface
+                Stability Promise</ulink>.</para>
         </refsect1>
 
         <refsect1>
diff --git a/man/systemd.xml b/man/systemd.xml
index 428e17f63be..f0fea5d0fef 100644
--- a/man/systemd.xml
+++ b/man/systemd.xml
@@ -440,6 +440,11 @@
                 ideas behind systemd please refer to the <ulink
                 url="http://0pointer.de/blog/projects/systemd.html">Original
                 Design Document</ulink>.</para>
+
+                <para>Note that some but not all interfaces provided
+                by systemd are covered by the <ulink
+                url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface
+                Stability Promise</ulink>.</para>
         </refsect1>
 
         <refsect1>