diff --git a/contexthub/1.2/IContexthubCallback.hal b/contexthub/1.2/IContexthubCallback.hal
new file mode 100644
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+++ b/contexthub/1.2/IContexthubCallback.hal
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+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.hardware.contexthub@1.2;
+
+import @1.0::IContexthubCallback;
+
+interface IContexthubCallback extends @1.0::IContexthubCallback {
+    /**
+     * This callback is passed by the Contexthub service to the HAL
+     * implementation to allow the HAL to send asynchronous messages back
+     * to the service and registered clients of the ContextHub service.
+     *
+     * @param msg message that should be delivered to host app clients
+     *
+     */
+    handleClientMsg_1_2(ContextHubMsg msg);
+
+    /**
+     * This callback is passed by the Contexthub service to the HAL
+     * implementation to allow the HAL to send information about the
+     * currently loaded and active nanoapps on the hub.
+     *
+     * @param appInfo vector of HubAppinfo structure for each nanoApp
+     *                on the hub that can be enabled, disabled and
+     *                unloaded by the service. Any nanoApps that cannot
+     *                be controlled by the service must not be reported.
+     *                All nanoApps that can be controlled by the service
+     *                must be reported.
+     */
+    handleAppsInfo_1_2(vec<HubAppInfo> appInfo);
+};