[5190] Updated Kea User's Guide with a warning about renames.

doc/guide/agent.xml

@@ -141,6 +141,21 @@
       configuration is specified for the DHCPv4 and DHCPv6 services.
     </para>
 
+    <warning>
+      <simpara>
+        We have renamed "dhcp4-server", "dhcp6-server" and "d2-server"
+        to "dhcp4", "dhcp6" and "d2" respectively after release of Kea 1.2.
+        If you are migrating from Kea 1.2 you need to tweak your CA config
+        to use this new naming convention. We have made this incompatible
+        change to facilitate future use cases where it will be possible to
+        specify additional values of the "service" parameter to point to
+        the particular instances of the Kea servers, e.g. "dhcp4/3"
+        pointing to the 3rd instance of the DHCPv4 server in the
+        multi-processed configuration. This is not yet supported but the
+        current renaming lays the ground for it.
+      </simpara>
+    </warning>
+
     <para>
       Hooks libraries can be attached to the Control Agent just like to
       DHCPv4 and DHCPv6 servers. It currently supports one hook point