diff --git a/transport/manager/1.2/IClientCallback.hal b/transport/manager/1.2/IClientCallback.hal
index 030bcd0..1189e44 100644
--- a/transport/manager/1.2/IClientCallback.hal
+++ b/transport/manager/1.2/IClientCallback.hal
@@ -18,9 +18,15 @@
 
 interface IClientCallback {
     /**
-     * Called when there are no clients remaining for the HAL registered with this service.
+     * This is called when there is a transition between having >= 1 clients and having 0 clients
+     * (or vice versa).
      *
      * @param registered binder 'server' registered with IServiceManager's registerClientCallback
+     * @param hasClients whether there are currently clients
+     *     true - when there are >= 1 clients. This must be called as soon as IServiceManager::get
+     *         is called (no race).
+     *     false - when there are 0 clients. This may be delayed if it is thought that another
+     *         may be used again soon.
      */
-    oneway onNoClients(interface registered);
+    oneway onClients(interface registered, bool hasClients);
 };
diff --git a/transport/manager/1.2/IServiceManager.hal b/transport/manager/1.2/IServiceManager.hal
index 8d34fb6..ae3fdfd 100644
--- a/transport/manager/1.2/IServiceManager.hal
+++ b/transport/manager/1.2/IServiceManager.hal
@@ -29,7 +29,8 @@
     /**
      * Adds a callback that must be called when the specified server has no clients.
      *
-     * This must only be called after the first time the service has no clients.
+     * If the service has clients at the time of registration, the callback is called with
+     * hasClients true. After that, it is called based on the changes in clientele.
      *
      * @param server non-null service waiting to have no clients
      * @param cb non-null callback to call when there are no clients