diff --git a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/AcquiredInfo.aidl b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/AcquiredInfo.aidl
index c19534c..eaa43f3 100644
--- a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/AcquiredInfo.aidl
+++ b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/AcquiredInfo.aidl
@@ -34,30 +34,31 @@
 package android.hardware.biometrics.face;
 @Backing(type="byte") @VintfStability
 enum AcquiredInfo {
-  GOOD = 0,
-  INSUFFICIENT = 1,
-  TOO_BRIGHT = 2,
-  TOO_DARK = 3,
-  TOO_CLOSE = 4,
-  TOO_FAR = 5,
-  FACE_TOO_HIGH = 6,
-  FACE_TOO_LOW = 7,
-  FACE_TOO_RIGHT = 8,
-  FACE_TOO_LEFT = 9,
-  POOR_GAZE = 10,
-  NOT_DETECTED = 11,
-  TOO_MUCH_MOTION = 12,
-  RECALIBRATE = 13,
-  TOO_DIFFERENT = 14,
-  TOO_SIMILAR = 15,
-  PAN_TOO_EXTREME = 16,
-  TILT_TOO_EXTREME = 17,
-  ROLL_TOO_EXTREME = 18,
-  FACE_OBSCURED = 19,
-  START = 20,
-  SENSOR_DIRTY = 21,
-  VENDOR = 22,
-  FIRST_FRAME_RECEIVED = 23,
-  DARK_GLASSES_DETECTED = 24,
-  MOUTH_COVERING_DETECTED = 25,
+  UNKNOWN = 0,
+  GOOD = 1,
+  INSUFFICIENT = 2,
+  TOO_BRIGHT = 3,
+  TOO_DARK = 4,
+  TOO_CLOSE = 5,
+  TOO_FAR = 6,
+  FACE_TOO_HIGH = 7,
+  FACE_TOO_LOW = 8,
+  FACE_TOO_RIGHT = 9,
+  FACE_TOO_LEFT = 10,
+  POOR_GAZE = 11,
+  NOT_DETECTED = 12,
+  TOO_MUCH_MOTION = 13,
+  RECALIBRATE = 14,
+  TOO_DIFFERENT = 15,
+  TOO_SIMILAR = 16,
+  PAN_TOO_EXTREME = 17,
+  TILT_TOO_EXTREME = 18,
+  ROLL_TOO_EXTREME = 19,
+  FACE_OBSCURED = 20,
+  START = 21,
+  SENSOR_DIRTY = 22,
+  VENDOR = 23,
+  FIRST_FRAME_RECEIVED = 24,
+  DARK_GLASSES_DETECTED = 25,
+  MOUTH_COVERING_DETECTED = 26,
 }
diff --git a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/BaseFrame.aidl b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/BaseFrame.aidl
index aa51343..67b5cf4 100644
--- a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/BaseFrame.aidl
+++ b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/BaseFrame.aidl
@@ -34,7 +34,7 @@
 package android.hardware.biometrics.face;
 @VintfStability
 parcelable BaseFrame {
-  android.hardware.biometrics.face.AcquiredInfo acquiredInfo = android.hardware.biometrics.face.AcquiredInfo.INSUFFICIENT;
+  android.hardware.biometrics.face.AcquiredInfo acquiredInfo = android.hardware.biometrics.face.AcquiredInfo.UNKNOWN;
   int vendorCode;
   float pan;
   float tilt;
diff --git a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/EnrollmentFrame.aidl b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/EnrollmentFrame.aidl
index 982e759..0ea10d6 100644
--- a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/EnrollmentFrame.aidl
+++ b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/EnrollmentFrame.aidl
@@ -35,6 +35,6 @@
 @VintfStability
 parcelable EnrollmentFrame {
   @nullable android.hardware.biometrics.face.Cell cell;
-  android.hardware.biometrics.face.EnrollmentStage stage = android.hardware.biometrics.face.EnrollmentStage.FIRST_FRAME_RECEIVED;
+  android.hardware.biometrics.face.EnrollmentStage stage = android.hardware.biometrics.face.EnrollmentStage.UNKNOWN;
   android.hardware.biometrics.face.BaseFrame data;
 }
diff --git a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/EnrollmentStage.aidl b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/EnrollmentStage.aidl
index 6be6e0b..ce5679a 100644
--- a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/EnrollmentStage.aidl
+++ b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/EnrollmentStage.aidl
@@ -34,10 +34,11 @@
 package android.hardware.biometrics.face;
 @Backing(type="byte") @VintfStability
 enum EnrollmentStage {
-  FIRST_FRAME_RECEIVED = 0,
-  WAITING_FOR_CENTERING = 1,
-  HOLD_STILL_IN_CENTER = 2,
-  ENROLLING_MOVEMENT_1 = 3,
-  ENROLLING_MOVEMENT_2 = 4,
-  ENROLLMENT_FINISHED = 5,
+  UNKNOWN = 0,
+  FIRST_FRAME_RECEIVED = 1,
+  WAITING_FOR_CENTERING = 2,
+  HOLD_STILL_IN_CENTER = 3,
+  ENROLLING_MOVEMENT_1 = 4,
+  ENROLLING_MOVEMENT_2 = 5,
+  ENROLLMENT_FINISHED = 6,
 }
diff --git a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/EnrollmentStageConfig.aidl b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/EnrollmentStageConfig.aidl
index 232bd52..48db2cf 100644
--- a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/EnrollmentStageConfig.aidl
+++ b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/EnrollmentStageConfig.aidl
@@ -34,6 +34,6 @@
 package android.hardware.biometrics.face;
 @VintfStability
 parcelable EnrollmentStageConfig {
-  android.hardware.biometrics.face.EnrollmentStage stage = android.hardware.biometrics.face.EnrollmentStage.FIRST_FRAME_RECEIVED;
+  android.hardware.biometrics.face.EnrollmentStage stage = android.hardware.biometrics.face.EnrollmentStage.UNKNOWN;
   List<android.hardware.biometrics.face.Cell> cells;
 }
diff --git a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/Error.aidl b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/Error.aidl
index 0437f07..1a21661 100644
--- a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/Error.aidl
+++ b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/Error.aidl
@@ -34,12 +34,13 @@
 package android.hardware.biometrics.face;
 @Backing(type="byte") @VintfStability
 enum Error {
+  UNKNOWN = 0,
   HW_UNAVAILABLE = 1,
   UNABLE_TO_PROCESS = 2,
   TIMEOUT = 3,
   NO_SPACE = 4,
   CANCELED = 5,
   UNABLE_TO_REMOVE = 6,
-  VENDOR = 8,
-  REENROLL_REQUIRED = 16,
+  VENDOR = 7,
+  REENROLL_REQUIRED = 8,
 }
diff --git a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/ISession.aidl b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/ISession.aidl
index 1ee3caf..d1c2c1d 100644
--- a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/ISession.aidl
+++ b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/ISession.aidl
@@ -36,6 +36,7 @@
 interface ISession {
   void generateChallenge();
   void revokeChallenge(in long challenge);
+  android.hardware.biometrics.face.EnrollmentStageConfig[] getEnrollmentConfig(in android.hardware.biometrics.face.EnrollmentType enrollmentType);
   android.hardware.biometrics.common.ICancellationSignal enroll(in android.hardware.keymaster.HardwareAuthToken hat, in android.hardware.biometrics.face.EnrollmentType type, in android.hardware.biometrics.face.Feature[] features, in android.hardware.common.NativeHandle previewSurface);
   android.hardware.biometrics.common.ICancellationSignal authenticate(in long operationId);
   android.hardware.biometrics.common.ICancellationSignal detectInteraction();
diff --git a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/SensorProps.aidl b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/SensorProps.aidl
index c55a600..e6ea9f9 100644
--- a/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/SensorProps.aidl
+++ b/biometrics/face/aidl/aidl_api/android.hardware.biometrics.face/current/android/hardware/biometrics/face/SensorProps.aidl
@@ -35,7 +35,7 @@
 @VintfStability
 parcelable SensorProps {
   android.hardware.biometrics.common.CommonProps commonProps;
-  android.hardware.biometrics.face.FaceSensorType sensorType = android.hardware.biometrics.face.FaceSensorType.RGB;
+  android.hardware.biometrics.face.FaceSensorType sensorType = android.hardware.biometrics.face.FaceSensorType.UNKNOWN;
   boolean halControlsPreview;
   int enrollPreviewWidth;
   int enrollPreviewHeight;
diff --git a/biometrics/face/aidl/android/hardware/biometrics/face/AcquiredInfo.aidl b/biometrics/face/aidl/android/hardware/biometrics/face/AcquiredInfo.aidl
index a3b229e..cf68421 100644
--- a/biometrics/face/aidl/android/hardware/biometrics/face/AcquiredInfo.aidl
+++ b/biometrics/face/aidl/android/hardware/biometrics/face/AcquiredInfo.aidl
@@ -19,18 +19,24 @@
 @VintfStability
 @Backing(type="byte")
 enum AcquiredInfo {
+    /**
+     * Placeholder value used for default initialization of AcquiredInfo. This
+     * value means AcquiredInfo wasn't explicitly initialized and must be
+     * discarded by the recipient.
+     */
+    UNKNOWN,
 
     /**
      * The acquired face data was good, no further user interaction is necessary.
      */
-    GOOD = 0,
+    GOOD,
 
     /**
      * The acquired face data was too noisy or did not have sufficient detail.
      * This is a catch-all for all acquisition errors not captured by the other
      * constants.
      */
-    INSUFFICIENT = 1,
+    INSUFFICIENT,
 
     /**
      * Because there was too much ambient light, the captured face data was too
@@ -40,7 +46,7 @@
      * The user is expected to take action to retry the operation in better
      * lighting conditions when this is returned.
      */
-    TOO_BRIGHT = 2,
+    TOO_BRIGHT,
 
     /**
      * Because there was not enough illumination, the captured face data was too
@@ -50,7 +56,7 @@
      * The user is expected to take action to retry the operation in better
      * lighting conditions when this is returned.
      */
-    TOO_DARK = 3,
+    TOO_DARK,
 
     /**
      * The detected face is too close to the sensor, and the image cannot be
@@ -59,7 +65,7 @@
      * The user is expected to be informed to move further from the sensor when
      * this is returned.
      */
-    TOO_CLOSE = 4,
+    TOO_CLOSE,
 
     /**
      * The detected face is too small, as the user might be too far away from
@@ -68,7 +74,7 @@
      * The user is expected to be informed to move closer to the sensor when
      * this is returned.
      */
-    TOO_FAR = 5,
+    TOO_FAR,
 
     /**
      * Only the upper part of the face was detected. The sensor's field of view
@@ -77,7 +83,7 @@
      * The user should be informed to move up with respect to the sensor when
      * this is returned.
      */
-    FACE_TOO_HIGH = 6,
+    FACE_TOO_HIGH,
 
     /**
      * Only the lower part of the face was detected. The sensor's field of view
@@ -86,7 +92,7 @@
      * The user should be informed to move down with respect to the sensor when
      * this is returned.
      */
-    FACE_TOO_LOW = 7,
+    FACE_TOO_LOW,
 
     /**
      * Only the right part of the face was detected. The sensor's field of view
@@ -95,7 +101,7 @@
      * The user should be informed to move to the right with respect to the
      * sensor when this is returned.
      */
-    FACE_TOO_RIGHT = 8,
+    FACE_TOO_RIGHT,
 
     /**
      * Only the left part of the face was detected. The sensor's field of view
@@ -104,7 +110,7 @@
      * The user should be informed to move to the left with respect to the
      * sensor when this is returned.
      */
-    FACE_TOO_LEFT = 9,
+    FACE_TOO_LEFT,
 
     /**
      * The user's eyes have strayed away from the sensor. If this message is
@@ -112,7 +118,7 @@
      * can't be found in the frame, one of the other acquisition messages
      * must be sent, e.g. NOT_DETECTED.
      */
-    POOR_GAZE = 10,
+    POOR_GAZE,
 
     /**
      * No face was detected within the sensor's field of view.
@@ -120,7 +126,7 @@
      * The user should be informed to point the sensor to a face when this is
      * returned.
      */
-    NOT_DETECTED = 11,
+    NOT_DETECTED,
 
     /**
      * Too much motion was detected.
@@ -128,7 +134,7 @@
      * The user should be informed to keep their face steady relative to the
      * sensor.
      */
-    TOO_MUCH_MOTION = 12,
+    TOO_MUCH_MOTION,
 
     /**
      * The sensor needs to be re-calibrated. This is an unexpected condition,
@@ -137,20 +143,20 @@
      * re-enrolling. The expected response to this message is to direct the
      * user to re-enroll.
      */
-    RECALIBRATE = 13,
+    RECALIBRATE,
 
     /**
      * The face is too different from a previous acquisition. This condition
      * only applies to enrollment. This can happen if the user passes the
      * device to someone else in the middle of enrollment.
      */
-    TOO_DIFFERENT = 14,
+    TOO_DIFFERENT,
 
     /**
      * The face is too similar to a previous acquisition. This condition only
      * applies to enrollment. The user should change their pose.
      */
-    TOO_SIMILAR = 15,
+    TOO_SIMILAR,
 
     /**
      * The magnitude of the pan angle of the user’s face with respect to the sensor’s
@@ -162,7 +168,7 @@
      *
      * The user should be informed to look more directly at the camera.
      */
-    PAN_TOO_EXTREME = 16,
+    PAN_TOO_EXTREME,
 
     /**
      * The magnitude of the tilt angle of the user’s face with respect to the sensor’s
@@ -173,7 +179,7 @@
      *
      * The user should be informed to look more directly at the camera.
      */
-    TILT_TOO_EXTREME = 17,
+    TILT_TOO_EXTREME,
 
     /**
      * The magnitude of the roll angle of the user’s face with respect to the sensor’s
@@ -185,7 +191,7 @@
      *
      * The user should be informed to look more directly at the camera.
      */
-    ROLL_TOO_EXTREME = 18,
+    ROLL_TOO_EXTREME,
 
     /**
      * The user’s face has been obscured by some object.
@@ -193,7 +199,7 @@
      * The user should be informed to remove any objects from the line of sight from
      * the sensor to the user’s face.
      */
-    FACE_OBSCURED = 19,
+    FACE_OBSCURED,
 
     /**
      * This message represents the earliest message sent at the beginning of the authentication
@@ -202,33 +208,33 @@
      * will measure latency based on the time between the last START message and the onAuthenticated
      * callback.
      */
-    START = 20,
+    START,
 
     /**
      * The sensor is dirty. The user should be informed to clean the sensor.
      */
-    SENSOR_DIRTY = 21,
+    SENSOR_DIRTY,
 
     /**
      * Vendor-specific acquisition message. See ISessionCallback#onAcquired vendorCode
      * documentation.
      */
-    VENDOR = 22,
+    VENDOR,
 
     /**
      * The first frame from the camera has been received.
      */
-    FIRST_FRAME_RECEIVED = 23,
+    FIRST_FRAME_RECEIVED,
 
     /**
      * Dark glasses detected. This can be useful for providing relevant feedback to the user and
      * enabling an alternative authentication logic if the implementation supports it.
      */
-    DARK_GLASSES_DETECTED = 24,
+    DARK_GLASSES_DETECTED,
 
     /**
      * A face mask or face covering detected. This can be useful for providing relevant feedback to
      * the user and enabling an alternative authentication logic if the implementation supports it.
      */
-    MOUTH_COVERING_DETECTED = 25,
+    MOUTH_COVERING_DETECTED,
 }
diff --git a/biometrics/face/aidl/android/hardware/biometrics/face/AuthenticationFrame.aidl b/biometrics/face/aidl/android/hardware/biometrics/face/AuthenticationFrame.aidl
index 47cad3c..be61a20 100644
--- a/biometrics/face/aidl/android/hardware/biometrics/face/AuthenticationFrame.aidl
+++ b/biometrics/face/aidl/android/hardware/biometrics/face/AuthenticationFrame.aidl
@@ -23,7 +23,6 @@
  */
 @VintfStability
 parcelable AuthenticationFrame {
-
     /**
      * The frame metadata. Can be used by the framework to provide user feedback.
      */
diff --git a/biometrics/face/aidl/android/hardware/biometrics/face/BaseFrame.aidl b/biometrics/face/aidl/android/hardware/biometrics/face/BaseFrame.aidl
index 85535f9..58ad01a 100644
--- a/biometrics/face/aidl/android/hardware/biometrics/face/BaseFrame.aidl
+++ b/biometrics/face/aidl/android/hardware/biometrics/face/BaseFrame.aidl
@@ -29,7 +29,7 @@
      * Information about the frame that can be used by the framework to provide feedback to the
      * user, for example ask the user to move their face in a certain way.
      */
-    AcquiredInfo acquiredInfo = AcquiredInfo.INSUFFICIENT;
+    AcquiredInfo acquiredInfo = AcquiredInfo.UNKNOWN;
 
     /**
      * If acquiredInfo is set to AcquiredInfo::VENDOR. This is the index into the configuration
diff --git a/biometrics/face/aidl/android/hardware/biometrics/face/EnrollmentFrame.aidl b/biometrics/face/aidl/android/hardware/biometrics/face/EnrollmentFrame.aidl
index ea0a502..ecb0e79 100644
--- a/biometrics/face/aidl/android/hardware/biometrics/face/EnrollmentFrame.aidl
+++ b/biometrics/face/aidl/android/hardware/biometrics/face/EnrollmentFrame.aidl
@@ -33,7 +33,7 @@
     /**
      * The enrollment stage for which this frame was captured.
      */
-    EnrollmentStage stage = EnrollmentStage.FIRST_FRAME_RECEIVED;
+    EnrollmentStage stage = EnrollmentStage.UNKNOWN;
 
     /**
      * The frame metadata. Can be used by the framework to provide user feedback.
diff --git a/biometrics/face/aidl/android/hardware/biometrics/face/EnrollmentStage.aidl b/biometrics/face/aidl/android/hardware/biometrics/face/EnrollmentStage.aidl
index bbc874f..5974838 100644
--- a/biometrics/face/aidl/android/hardware/biometrics/face/EnrollmentStage.aidl
+++ b/biometrics/face/aidl/android/hardware/biometrics/face/EnrollmentStage.aidl
@@ -22,34 +22,40 @@
 @VintfStability
 @Backing(type="byte")
 enum EnrollmentStage {
+    /**
+     * Placeholder value used for default initialization of EnrollmentStage. This
+     * value means EnrollmentStage wasn't explicitly initialized and must be
+     * discarded by the recipient.
+     */
+    UNKNOWN,
 
-  /**
-   * HAL has obtained the first camera frame.
-   */
-   FIRST_FRAME_RECEIVED,
+    /**
+     * HAL has obtained the first camera frame.
+     */
+    FIRST_FRAME_RECEIVED,
 
-  /**
-   * HAL is waiting for the user's face to be centered.
-   */
-   WAITING_FOR_CENTERING,
+    /**
+     * HAL is waiting for the user's face to be centered.
+     */
+    WAITING_FOR_CENTERING,
 
-  /**
-   * HAL is expecting the user's face to stay centered.
-   */
-   HOLD_STILL_IN_CENTER,
+    /**
+     * HAL is expecting the user's face to stay centered.
+     */
+    HOLD_STILL_IN_CENTER,
 
-  /**
-   * Vendor defined movement 1.
-   */
-   ENROLLING_MOVEMENT_1,
+    /**
+     * Vendor defined movement 1.
+     */
+    ENROLLING_MOVEMENT_1,
 
-  /**
-   * Vendor defined movement 2.
-   */
-   ENROLLING_MOVEMENT_2,
+    /**
+     * Vendor defined movement 2.
+     */
+    ENROLLING_MOVEMENT_2,
 
-  /**
-   * HAL has finished the enrollment.
-   */
-   ENROLLMENT_FINISHED,
+    /**
+     * HAL has finished the enrollment.
+     */
+    ENROLLMENT_FINISHED,
 }
diff --git a/biometrics/face/aidl/android/hardware/biometrics/face/EnrollmentStageConfig.aidl b/biometrics/face/aidl/android/hardware/biometrics/face/EnrollmentStageConfig.aidl
index 3c31fcc..a8fa9ab 100644
--- a/biometrics/face/aidl/android/hardware/biometrics/face/EnrollmentStageConfig.aidl
+++ b/biometrics/face/aidl/android/hardware/biometrics/face/EnrollmentStageConfig.aidl
@@ -24,7 +24,7 @@
     /**
      * The stage that's being configured.
      */
-    EnrollmentStage stage = EnrollmentStage.FIRST_FRAME_RECEIVED;
+    EnrollmentStage stage = EnrollmentStage.UNKNOWN;
 
     /**
      * Optional list of cells that must be completed to finish this stage.
diff --git a/biometrics/face/aidl/android/hardware/biometrics/face/Error.aidl b/biometrics/face/aidl/android/hardware/biometrics/face/Error.aidl
index 6f3264b..e99415a 100644
--- a/biometrics/face/aidl/android/hardware/biometrics/face/Error.aidl
+++ b/biometrics/face/aidl/android/hardware/biometrics/face/Error.aidl
@@ -20,22 +20,22 @@
 @Backing(type="byte")
 enum Error {
     /**
-     * Reserved for testing and to keep subsequent numbering consistent with
-     * older interfaces.
-     *
-     * NO_ERROR = 0,
+     * Placeholder value used for default initialization of Error. This value
+     * means Error wasn't explicitly initialized and must be discarded by the
+     * recipient.
      */
+    UNKNOWN,
 
     /**
      * A hardware error has occurred that cannot be resolved. Try again later.
      */
-    HW_UNAVAILABLE = 1,
+    HW_UNAVAILABLE,
 
     /**
      * The current operation could not be completed, e.g. the sensor was unable
      * to process the current image or the HAT was invalid.
      */
-    UNABLE_TO_PROCESS = 2,
+    UNABLE_TO_PROCESS,
 
     /**
      * The current operation took too long to complete. This is intended to
@@ -48,48 +48,34 @@
      * indicate that the implementation is no longer looking and the framework
      * should restart the operation on the next user interaction.
      */
-    TIMEOUT = 3,
+    TIMEOUT,
 
     /**
      * The current operation could not be completed because there is not enough
      * storage space remaining to do so.
      */
-    NO_SPACE = 4,
+    NO_SPACE,
 
     /**
      * The current operation has been cancelled. This may happen if a new
      * request (authenticate, remove, enumerate, enroll) is initiated while
      * an on-going operation is in progress, or if cancel() was called.
      */
-    CANCELED = 5,
+    CANCELED,
 
     /**
      * The current remove operation could not be completed; the face template
      * provided could not be removed.
      */
-    UNABLE_TO_REMOVE = 6,
-
-    /**
-     * Reserved to maintain backwards compatibility. See
-     * ISessionCallback#onLockoutTimed instead.
-     *
-     * LOCKOUT = 7,
-     */
+    UNABLE_TO_REMOVE,
 
     /**
      * Used to enable a vendor-specific error message.
      */
-    VENDOR = 8,
-
-    /**
-     * Reserved to maintain backwards compatibility. See
-     * ISessionCallback#onLockoutPermanent instead.
-     *
-     * LOCKOUT_PERMANENT = 9
-     */
+    VENDOR,
 
     /**
      * Authentication cannot be performed because re-enrollment is required.
      */
-    REENROLL_REQUIRED = 16,
+    REENROLL_REQUIRED,
 }
diff --git a/biometrics/face/aidl/android/hardware/biometrics/face/ISession.aidl b/biometrics/face/aidl/android/hardware/biometrics/face/ISession.aidl
index 12911e3..a9a8c16 100644
--- a/biometrics/face/aidl/android/hardware/biometrics/face/ISession.aidl
+++ b/biometrics/face/aidl/android/hardware/biometrics/face/ISession.aidl
@@ -17,6 +17,7 @@
 package android.hardware.biometrics.face;
 
 import android.hardware.biometrics.common.ICancellationSignal;
+import android.hardware.biometrics.face.EnrollmentStageConfig;
 import android.hardware.biometrics.face.EnrollmentType;
 import android.hardware.biometrics.face.Feature;
 import android.hardware.common.NativeHandle;
@@ -104,9 +105,9 @@
      * each of the stages.
      *
      * @param enrollmentType See the EnrollmentType enum.
-     * @return A list of EnrollmentStageConfig that describes each enrollment stage.
-     *
-    List<EnrollmentStageConfig> getEnrollmentConfig(in EnrollmentType enrollmentType);
+     * @return An EnrollmentStageConfig array that describes each enrollment stage.
+     */
+    EnrollmentStageConfig[] getEnrollmentConfig(in EnrollmentType enrollmentType);
 
     /**
      * enroll:
diff --git a/biometrics/face/aidl/android/hardware/biometrics/face/SensorProps.aidl b/biometrics/face/aidl/android/hardware/biometrics/face/SensorProps.aidl
index b11b436..994324d 100644
--- a/biometrics/face/aidl/android/hardware/biometrics/face/SensorProps.aidl
+++ b/biometrics/face/aidl/android/hardware/biometrics/face/SensorProps.aidl
@@ -29,7 +29,7 @@
     /**
      * A statically configured sensor type representing this face sensor.
      */
-    FaceSensorType sensorType = FaceSensorType.RGB;
+    FaceSensorType sensorType = FaceSensorType.UNKNOWN;
 
     /**
      * Whether or not the HAL is responsible for showing the face enrollment preview to the user.
diff --git a/biometrics/face/aidl/default/Session.cpp b/biometrics/face/aidl/default/Session.cpp
index 4438d35..d980c5f 100644
--- a/biometrics/face/aidl/default/Session.cpp
+++ b/biometrics/face/aidl/default/Session.cpp
@@ -52,6 +52,12 @@
     return ndk::ScopedAStatus::ok();
 }
 
+ndk::ScopedAStatus Session::getEnrollmentConfig(EnrollmentType /*enrollmentType*/,
+                                                std::vector<EnrollmentStageConfig>* return_val) {
+    *return_val = {};
+    return ndk::ScopedAStatus::ok();
+}
+
 ndk::ScopedAStatus Session::enroll(
         const keymaster::HardwareAuthToken& /*hat*/, EnrollmentType /*enrollmentType*/,
         const std::vector<Feature>& /*features*/, const NativeHandle& /*previewSurface*/,
diff --git a/biometrics/face/aidl/default/Session.h b/biometrics/face/aidl/default/Session.h
index c89985e..caf81f8 100644
--- a/biometrics/face/aidl/default/Session.h
+++ b/biometrics/face/aidl/default/Session.h
@@ -34,6 +34,9 @@
 
     ndk::ScopedAStatus revokeChallenge(int64_t challenge) override;
 
+    ndk::ScopedAStatus getEnrollmentConfig(EnrollmentType enrollmentType,
+                                           std::vector<EnrollmentStageConfig>* return_val) override;
+
     ndk::ScopedAStatus enroll(const keymaster::HardwareAuthToken& hat,
                               EnrollmentType enrollmentType, const std::vector<Feature>& features,
                               const NativeHandle& previewSurface,