diff --git a/doc/sphinx/arm/agent.rst b/doc/sphinx/arm/agent.rst
index 0ace3cad7c..1c5fd253d0 100644
--- a/doc/sphinx/arm/agent.rst
+++ b/doc/sphinx/arm/agent.rst
@@ -150,6 +150,16 @@ for the DHCPv4 server and the CA (for that server) must match. Consult
 :ref:`d2-unix-ctrl-channel` to learn how the UNIX socket configuration is
 specified for the DHCPv4, DHCPv6, and D2 services.
 
+.. note::
+
+    As of Kea 2.7.9, control sockets may reside only in the directory
+    determined during compilation as ``"[kea-install-dir]/var/run/kea"``. This
+    path may be overridden at startup by setting the environment variable
+    ``KEA_CONTROL_SOCKET_DIR`` to the desired path.  If a path other than
+    this value is used in ``socket-name``, Kea will emit an error and refuse to
+    start or, if already running, log an unrecoverable error.  For ease of use in
+    simply omit the path component from ``socket-name`` entries.
+
 User contexts can store arbitrary data as long as they are in valid JSON
 syntax and their top-level element is a map (i.e. the data must be
 enclosed in curly brackets). Some hook libraries may expect specific
diff --git a/doc/sphinx/arm/ddns.rst b/doc/sphinx/arm/ddns.rst
index 129082c296..a13b70f83c 100644
--- a/doc/sphinx/arm/ddns.rst
+++ b/doc/sphinx/arm/ddns.rst
@@ -326,7 +326,7 @@ Kea supports only one ``unix`` control socket in the "control-sockets" list.
 
 .. note::
 
-    As of Kea 2.7.9, control sockets may reside in the directory
+    As of Kea 2.7.9, control sockets may only reside in the directory
     determined during compilation as ``"[kea-install-dir]/var/run/kea"``. This
     path may be overridden at startup by setting the environment variable
     ``KEA_CONTROL_SOCKET_DIR`` to the desired path.  If a path other than
diff --git a/doc/sphinx/arm/dhcp4-srv.rst b/doc/sphinx/arm/dhcp4-srv.rst
index fcb071dab7..1a480140b6 100644
--- a/doc/sphinx/arm/dhcp4-srv.rst
+++ b/doc/sphinx/arm/dhcp4-srv.rst
@@ -7838,7 +7838,7 @@ Kea supports only one ``unix`` control socket in the "control-sockets" list.
 
 .. note::
 
-    As of Kea 2.7.9, control sockets may reside in the directory
+    As of Kea 2.7.9, control sockets may only reside in the directory
     determined during compilation as ``"[kea-install-dir]/var/run/kea"``. This
     path may be overridden at startup by setting the environment variable
     ``KEA_CONTROL_SOCKET_DIR`` to the desired path.  If a path other than