diff --git a/stable/Android.bp b/stable/Android.bp
new file mode 100644
index 0000000..01dd88b
--- /dev/null
+++ b/stable/Android.bp
@@ -0,0 +1,39 @@
+//
+// 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.
+//
+
+// Stable AIDL interface between update_engine and other APEXes
+// ========================================================
+aidl_interface {
+    name: "libupdate_engine_stable",
+    srcs: [
+        "android/os/IUpdateEngineStable.aidl",
+        "android/os/IUpdateEngineStableCallback.aidl",
+    ],
+    backend: {
+        cpp: {
+            enabled: true,
+        },
+        java: {
+            enabled: false,
+        },
+        ndk: {
+            enabled: true,
+            apex_available: [
+                "com.android.gki.*",
+            ],
+        },
+    },
+}
diff --git a/stable/aidl_api/libupdate_engine_stable/current/android/os/IUpdateEngineStable.aidl b/stable/aidl_api/libupdate_engine_stable/current/android/os/IUpdateEngineStable.aidl
new file mode 100644
index 0000000..82c3ca5
--- /dev/null
+++ b/stable/aidl_api/libupdate_engine_stable/current/android/os/IUpdateEngineStable.aidl
@@ -0,0 +1,23 @@
+///////////////////////////////////////////////////////////////////////////////
+// THIS FILE IS IMMUTABLE. DO NOT EDIT IN ANY CASE.                          //
+///////////////////////////////////////////////////////////////////////////////
+
+// This file is a snapshot of an AIDL interface (or parcelable). Do not try to
+// edit this file. It looks like you are doing that because you have modified
+// an AIDL interface in a backward-incompatible way, e.g., deleting a function
+// from an interface or a field from a parcelable and it broke the build. That
+// breakage is intended.
+//
+// You must not make a backward incompatible changes to the AIDL files built
+// with the aidl_interface module type with versions property set. The module
+// type is used to build AIDL files in a way that they can be used across
+// independently updatable components of the system. If a device is shipped
+// with such a backward incompatible change, it has a high risk of breaking
+// later when a module using the interface is updated, e.g., Mainline modules.
+
+package android.os;
+interface IUpdateEngineStable {
+  void applyPayloadFd(in ParcelFileDescriptor pfd, in long payload_offset, in long payload_size, in String[] headerKeyValuePairs);
+  boolean bind(android.os.IUpdateEngineStableCallback callback);
+  boolean unbind(android.os.IUpdateEngineStableCallback callback);
+}
diff --git a/stable/aidl_api/libupdate_engine_stable/current/android/os/IUpdateEngineStableCallback.aidl b/stable/aidl_api/libupdate_engine_stable/current/android/os/IUpdateEngineStableCallback.aidl
new file mode 100644
index 0000000..4c72b49
--- /dev/null
+++ b/stable/aidl_api/libupdate_engine_stable/current/android/os/IUpdateEngineStableCallback.aidl
@@ -0,0 +1,22 @@
+///////////////////////////////////////////////////////////////////////////////
+// THIS FILE IS IMMUTABLE. DO NOT EDIT IN ANY CASE.                          //
+///////////////////////////////////////////////////////////////////////////////
+
+// This file is a snapshot of an AIDL interface (or parcelable). Do not try to
+// edit this file. It looks like you are doing that because you have modified
+// an AIDL interface in a backward-incompatible way, e.g., deleting a function
+// from an interface or a field from a parcelable and it broke the build. That
+// breakage is intended.
+//
+// You must not make a backward incompatible changes to the AIDL files built
+// with the aidl_interface module type with versions property set. The module
+// type is used to build AIDL files in a way that they can be used across
+// independently updatable components of the system. If a device is shipped
+// with such a backward incompatible change, it has a high risk of breaking
+// later when a module using the interface is updated, e.g., Mainline modules.
+
+package android.os;
+interface IUpdateEngineStableCallback {
+  oneway void onStatusUpdate(int status_code, float percentage);
+  oneway void onPayloadApplicationComplete(int error_code);
+}
diff --git a/stable/android/os/IUpdateEngineStable.aidl b/stable/android/os/IUpdateEngineStable.aidl
new file mode 100644
index 0000000..b3b6674
--- /dev/null
+++ b/stable/android/os/IUpdateEngineStable.aidl
@@ -0,0 +1,75 @@
+/*
+ * 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.os;
+
+import android.os.IUpdateEngineStableCallback;
+import android.os.ParcelFileDescriptor;
+
+/**
+ * The stable interface exposed by the update engine daemon.
+ */
+interface IUpdateEngineStable {
+  /**
+   * Apply the given payload as provided in the given file descriptor.
+   *
+   * See {@link #bind(IUpdateEngineCallback)} for status updates.
+   *
+   * @param pfd The file descriptor opened at the payload file. Note that the daemon must have
+   *   enough permission to operate on the file descriptor.
+   * @param payload_offset offset into pfd where the payload binary starts.
+   * @param payload_size length after payload_offset to read from pfd. If 0, it will be auto
+   *   detected.
+   * @param headerKeyValuePairs additional header key value pairs, in the format of "key=value".
+   * @see android.os.UpdateEngine#applyPayload(android.content.res.AssetFileDescriptor, String[])
+   */
+  void applyPayloadFd(in ParcelFileDescriptor pfd,
+                      in long payload_offset,
+                      in long payload_size,
+                      in String[] headerKeyValuePairs);
+
+  /**
+   * Bind a callback for status updates on payload application.
+   *
+   * At any given time, only one callback can be bound. If a callback is already bound,
+   * subsequent binding will fail and return false until the bound callback is unbound. That is,
+   * binding is first-come, first-serve.
+   *
+   * A bound callback may be unbound explicitly by calling
+   * {@link #unbind(IUpdateEngineStableCallback)}, or
+   * implicitly when the process implementing the callback dies.
+   *
+   * @param callback See {@link IUpdateEngineStableCallback}
+   * @return true if binding is successful, false otherwise.
+   * @see android.os.UpdateEngine#bind(android.os.UpdateEngineCallback)
+   */
+  boolean bind(IUpdateEngineStableCallback callback);
+
+  /**
+   * Unbind a possibly bound callback.
+   *
+   * If the provided callback does not match the previously bound callback, unbinding fails.
+   *
+   * Note that a callback may also be unbound when the process implementing the callback dies.
+   * Hence, a client usually does not need to explicitly unbind a callback unless it wants to change
+   * the bound callback.
+   *
+   * @param callback The callback to be unbound. See {@link IUpdateEngineStableCallback}.
+   * @return true if unbinding is successful, false otherwise.
+   * @see android.os.UpdateEngine#unbind(android.os.UpdateEngineCallback)
+   */
+  boolean unbind(IUpdateEngineStableCallback callback);
+}
diff --git a/stable/android/os/IUpdateEngineStableCallback.aidl b/stable/android/os/IUpdateEngineStableCallback.aidl
new file mode 100644
index 0000000..d8fc333
--- /dev/null
+++ b/stable/android/os/IUpdateEngineStableCallback.aidl
@@ -0,0 +1,39 @@
+/*
+ * 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.os;
+
+/**
+ * The stable Callback interface for IUpdateEngineStable.
+ */
+oneway interface IUpdateEngineStableCallback {
+  /**
+   * Invoked when a payload is being applied and there is a status update.
+   *
+   * @param status_code see {@link android.os.UpdateEngine.UpdateStatusConstants}.
+   * @param percentage percentage of progress of the current stage.
+   * @see android.os.UpdateEngineCallback#onStatusUpdate(int, float)
+   */
+  void onStatusUpdate(int status_code, float percentage);
+
+  /**
+   * Invoked when a payload has finished being applied.
+   *
+   * @param error_code see {@link android.os.UpdateEngine.ErrorCodeConstants}
+   * @see android.os.UpdateEngineCallback#onPayloadApplicationComplete(int)
+   */
+  void onPayloadApplicationComplete(int error_code);
+}