diff --git a/Tethering/common/TetheringLib/api/module-lib-current.txt b/Tethering/common/TetheringLib/api/module-lib-current.txt
index 8a7e975..e823e17 100644
--- a/Tethering/common/TetheringLib/api/module-lib-current.txt
+++ b/Tethering/common/TetheringLib/api/module-lib-current.txt
@@ -62,19 +62,20 @@
     field public static final int TETHERING_WIFI = 0; // 0x0
     field public static final int TETHERING_WIFI_P2P = 3; // 0x3
     field public static final int TETHER_ERROR_DHCPSERVER_ERROR = 12; // 0xc
-    field public static final int TETHER_ERROR_DISABLE_NAT_ERROR = 9; // 0x9
-    field public static final int TETHER_ERROR_ENABLE_NAT_ERROR = 8; // 0x8
+    field public static final int TETHER_ERROR_DISABLE_FORWARDING_ERROR = 9; // 0x9
+    field public static final int TETHER_ERROR_ENABLE_FORWARDING_ERROR = 8; // 0x8
     field public static final int TETHER_ERROR_ENTITLEMENT_UNKNOWN = 13; // 0xd
     field public static final int TETHER_ERROR_IFACE_CFG_ERROR = 10; // 0xa
-    field public static final int TETHER_ERROR_MASTER_ERROR = 5; // 0x5
+    field public static final int TETHER_ERROR_INTERNAL_ERROR = 5; // 0x5
     field public static final int TETHER_ERROR_NO_ACCESS_TETHERING_PERMISSION = 15; // 0xf
     field public static final int TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION = 14; // 0xe
     field public static final int TETHER_ERROR_NO_ERROR = 0; // 0x0
-    field public static final int TETHER_ERROR_PROVISION_FAILED = 11; // 0xb
+    field public static final int TETHER_ERROR_PROVISIONING_FAILED = 11; // 0xb
     field public static final int TETHER_ERROR_SERVICE_UNAVAIL = 2; // 0x2
     field public static final int TETHER_ERROR_TETHER_IFACE_ERROR = 6; // 0x6
     field public static final int TETHER_ERROR_UNAVAIL_IFACE = 4; // 0x4
     field public static final int TETHER_ERROR_UNKNOWN_IFACE = 1; // 0x1
+    field public static final int TETHER_ERROR_UNKNOWN_TYPE = 16; // 0x10
     field public static final int TETHER_ERROR_UNSUPPORTED = 3; // 0x3
     field public static final int TETHER_ERROR_UNTETHER_IFACE_ERROR = 7; // 0x7
     field public static final int TETHER_HARDWARE_OFFLOAD_FAILED = 2; // 0x2
@@ -86,29 +87,26 @@
     method public void onTetheringEntitlementResult(int);
   }
 
-  public abstract static class TetheringManager.StartTetheringCallback {
-    ctor public TetheringManager.StartTetheringCallback();
-    method public void onTetheringFailed(int);
-    method public void onTetheringStarted();
+  public static interface TetheringManager.StartTetheringCallback {
+    method public default void onTetheringFailed(int);
+    method public default void onTetheringStarted();
   }
 
-  public abstract static class TetheringManager.TetheringEventCallback {
-    ctor public TetheringManager.TetheringEventCallback();
-    method public void onClientsChanged(@NonNull java.util.Collection<android.net.TetheredClient>);
-    method public void onError(@NonNull String, int);
-    method public void onOffloadStatusChanged(int);
-    method @Deprecated public void onTetherableInterfaceRegexpsChanged(@NonNull android.net.TetheringManager.TetheringInterfaceRegexps);
-    method public void onTetherableInterfacesChanged(@NonNull java.util.List<java.lang.String>);
-    method public void onTetheredInterfacesChanged(@NonNull java.util.List<java.lang.String>);
-    method public void onTetheringSupported(boolean);
-    method public void onUpstreamChanged(@Nullable android.net.Network);
+  public static interface TetheringManager.TetheringEventCallback {
+    method public default void onClientsChanged(@NonNull java.util.Collection<android.net.TetheredClient>);
+    method public default void onError(@NonNull String, int);
+    method public default void onOffloadStatusChanged(int);
+    method public default void onTetherableInterfaceRegexpsChanged(@NonNull android.net.TetheringManager.TetheringInterfaceRegexps);
+    method public default void onTetherableInterfacesChanged(@NonNull java.util.List<java.lang.String>);
+    method public default void onTetheredInterfacesChanged(@NonNull java.util.List<java.lang.String>);
+    method public default void onTetheringSupported(boolean);
+    method public default void onUpstreamChanged(@Nullable android.net.Network);
   }
 
-  @Deprecated public static class TetheringManager.TetheringInterfaceRegexps {
-    ctor @Deprecated public TetheringManager.TetheringInterfaceRegexps(@NonNull String[], @NonNull String[], @NonNull String[]);
-    method @Deprecated @NonNull public java.util.List<java.lang.String> getTetherableBluetoothRegexs();
-    method @Deprecated @NonNull public java.util.List<java.lang.String> getTetherableUsbRegexs();
-    method @Deprecated @NonNull public java.util.List<java.lang.String> getTetherableWifiRegexs();
+  public static class TetheringManager.TetheringInterfaceRegexps {
+    method @NonNull public java.util.List<java.lang.String> getTetherableBluetoothRegexs();
+    method @NonNull public java.util.List<java.lang.String> getTetherableUsbRegexs();
+    method @NonNull public java.util.List<java.lang.String> getTetherableWifiRegexs();
   }
 
   public static class TetheringManager.TetheringRequest {
@@ -119,8 +117,11 @@
     method @NonNull public android.net.TetheringManager.TetheringRequest build();
     method @Nullable public android.net.LinkAddress getClientStaticIpv4Address();
     method @Nullable public android.net.LinkAddress getLocalIpv4Address();
+    method public boolean getShouldShowEntitlementUi();
+    method public int getTetheringType();
+    method public boolean isExemptFromEntitlementCheck();
     method @NonNull @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public android.net.TetheringManager.TetheringRequest.Builder setExemptFromEntitlementCheck(boolean);
-    method @NonNull @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public android.net.TetheringManager.TetheringRequest.Builder setSilentProvisioning(boolean);
+    method @NonNull @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public android.net.TetheringManager.TetheringRequest.Builder setShouldShowEntitlementUi(boolean);
     method @NonNull @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public android.net.TetheringManager.TetheringRequest.Builder setStaticIpv4Addresses(@NonNull android.net.LinkAddress, @NonNull android.net.LinkAddress);
   }
 
diff --git a/Tethering/common/TetheringLib/api/system-current.txt b/Tethering/common/TetheringLib/api/system-current.txt
index ac73953..3751135 100644
--- a/Tethering/common/TetheringLib/api/system-current.txt
+++ b/Tethering/common/TetheringLib/api/system-current.txt
@@ -40,19 +40,20 @@
     field public static final int TETHERING_WIFI = 0; // 0x0
     field public static final int TETHERING_WIFI_P2P = 3; // 0x3
     field public static final int TETHER_ERROR_DHCPSERVER_ERROR = 12; // 0xc
-    field public static final int TETHER_ERROR_DISABLE_NAT_ERROR = 9; // 0x9
-    field public static final int TETHER_ERROR_ENABLE_NAT_ERROR = 8; // 0x8
+    field public static final int TETHER_ERROR_DISABLE_FORWARDING_ERROR = 9; // 0x9
+    field public static final int TETHER_ERROR_ENABLE_FORWARDING_ERROR = 8; // 0x8
     field public static final int TETHER_ERROR_ENTITLEMENT_UNKNOWN = 13; // 0xd
     field public static final int TETHER_ERROR_IFACE_CFG_ERROR = 10; // 0xa
-    field public static final int TETHER_ERROR_MASTER_ERROR = 5; // 0x5
+    field public static final int TETHER_ERROR_INTERNAL_ERROR = 5; // 0x5
     field public static final int TETHER_ERROR_NO_ACCESS_TETHERING_PERMISSION = 15; // 0xf
     field public static final int TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION = 14; // 0xe
     field public static final int TETHER_ERROR_NO_ERROR = 0; // 0x0
-    field public static final int TETHER_ERROR_PROVISION_FAILED = 11; // 0xb
+    field public static final int TETHER_ERROR_PROVISIONING_FAILED = 11; // 0xb
     field public static final int TETHER_ERROR_SERVICE_UNAVAIL = 2; // 0x2
     field public static final int TETHER_ERROR_TETHER_IFACE_ERROR = 6; // 0x6
     field public static final int TETHER_ERROR_UNAVAIL_IFACE = 4; // 0x4
     field public static final int TETHER_ERROR_UNKNOWN_IFACE = 1; // 0x1
+    field public static final int TETHER_ERROR_UNKNOWN_TYPE = 16; // 0x10
     field public static final int TETHER_ERROR_UNSUPPORTED = 3; // 0x3
     field public static final int TETHER_ERROR_UNTETHER_IFACE_ERROR = 7; // 0x7
     field public static final int TETHER_HARDWARE_OFFLOAD_FAILED = 2; // 0x2
@@ -64,29 +65,19 @@
     method public void onTetheringEntitlementResult(int);
   }
 
-  public abstract static class TetheringManager.StartTetheringCallback {
-    ctor public TetheringManager.StartTetheringCallback();
-    method public void onTetheringFailed(int);
-    method public void onTetheringStarted();
+  public static interface TetheringManager.StartTetheringCallback {
+    method public default void onTetheringFailed(int);
+    method public default void onTetheringStarted();
   }
 
-  public abstract static class TetheringManager.TetheringEventCallback {
-    ctor public TetheringManager.TetheringEventCallback();
-    method public void onClientsChanged(@NonNull java.util.Collection<android.net.TetheredClient>);
-    method public void onError(@NonNull String, int);
-    method public void onOffloadStatusChanged(int);
-    method @Deprecated public void onTetherableInterfaceRegexpsChanged(@NonNull android.net.TetheringManager.TetheringInterfaceRegexps);
-    method public void onTetherableInterfacesChanged(@NonNull java.util.List<java.lang.String>);
-    method public void onTetheredInterfacesChanged(@NonNull java.util.List<java.lang.String>);
-    method public void onTetheringSupported(boolean);
-    method public void onUpstreamChanged(@Nullable android.net.Network);
-  }
-
-  @Deprecated public static class TetheringManager.TetheringInterfaceRegexps {
-    ctor @Deprecated public TetheringManager.TetheringInterfaceRegexps(@NonNull String[], @NonNull String[], @NonNull String[]);
-    method @Deprecated @NonNull public java.util.List<java.lang.String> getTetherableBluetoothRegexs();
-    method @Deprecated @NonNull public java.util.List<java.lang.String> getTetherableUsbRegexs();
-    method @Deprecated @NonNull public java.util.List<java.lang.String> getTetherableWifiRegexs();
+  public static interface TetheringManager.TetheringEventCallback {
+    method public default void onClientsChanged(@NonNull java.util.Collection<android.net.TetheredClient>);
+    method public default void onError(@NonNull String, int);
+    method public default void onOffloadStatusChanged(int);
+    method public default void onTetherableInterfacesChanged(@NonNull java.util.List<java.lang.String>);
+    method public default void onTetheredInterfacesChanged(@NonNull java.util.List<java.lang.String>);
+    method public default void onTetheringSupported(boolean);
+    method public default void onUpstreamChanged(@Nullable android.net.Network);
   }
 
   public static class TetheringManager.TetheringRequest {
@@ -97,8 +88,11 @@
     method @NonNull public android.net.TetheringManager.TetheringRequest build();
     method @Nullable public android.net.LinkAddress getClientStaticIpv4Address();
     method @Nullable public android.net.LinkAddress getLocalIpv4Address();
+    method public boolean getShouldShowEntitlementUi();
+    method public int getTetheringType();
+    method public boolean isExemptFromEntitlementCheck();
     method @NonNull @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public android.net.TetheringManager.TetheringRequest.Builder setExemptFromEntitlementCheck(boolean);
-    method @NonNull @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public android.net.TetheringManager.TetheringRequest.Builder setSilentProvisioning(boolean);
+    method @NonNull @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public android.net.TetheringManager.TetheringRequest.Builder setShouldShowEntitlementUi(boolean);
     method @NonNull @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public android.net.TetheringManager.TetheringRequest.Builder setStaticIpv4Addresses(@NonNull android.net.LinkAddress, @NonNull android.net.LinkAddress);
   }
 
diff --git a/Tethering/common/TetheringLib/src/android/net/TetheringManager.java b/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
index f2045df..86ef7f0 100644
--- a/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
+++ b/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
@@ -115,6 +115,19 @@
      */
     public static final String EXTRA_ERRORED_TETHER = "erroredArray";
 
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(flag = false, value = {
+            TETHERING_WIFI,
+            TETHERING_USB,
+            TETHERING_BLUETOOTH,
+            TETHERING_WIFI_P2P,
+            TETHERING_NCM,
+            TETHERING_ETHERNET,
+    })
+    public @interface TetheringType {
+    }
+
     /**
      * Invalid tethering type.
      * @see #startTethering.
@@ -158,22 +171,60 @@
      */
     public static final int TETHERING_ETHERNET = 5;
 
-    public static final int TETHER_ERROR_NO_ERROR           = 0;
-    public static final int TETHER_ERROR_UNKNOWN_IFACE      = 1;
-    public static final int TETHER_ERROR_SERVICE_UNAVAIL    = 2;
-    public static final int TETHER_ERROR_UNSUPPORTED        = 3;
-    public static final int TETHER_ERROR_UNAVAIL_IFACE      = 4;
-    public static final int TETHER_ERROR_MASTER_ERROR       = 5;
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(value = {
+            TETHER_ERROR_NO_ERROR,
+            TETHER_ERROR_PROVISIONING_FAILED,
+            TETHER_ERROR_ENTITLEMENT_UNKNOWN,
+    })
+    public @interface EntitlementResult {
+    }
+
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(value = {
+            TETHER_ERROR_NO_ERROR,
+            TETHER_ERROR_UNKNOWN_IFACE,
+            TETHER_ERROR_SERVICE_UNAVAIL,
+            TETHER_ERROR_INTERNAL_ERROR,
+            TETHER_ERROR_TETHER_IFACE_ERROR,
+            TETHER_ERROR_ENABLE_FORWARDING_ERROR,
+            TETHER_ERROR_DISABLE_FORWARDING_ERROR,
+            TETHER_ERROR_IFACE_CFG_ERROR,
+            TETHER_ERROR_DHCPSERVER_ERROR,
+    })
+    public @interface TetheringIfaceError {
+    }
+
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(value = {
+            TETHER_ERROR_SERVICE_UNAVAIL,
+            TETHER_ERROR_INTERNAL_ERROR,
+            TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION,
+            TETHER_ERROR_UNKNOWN_TYPE,
+    })
+    public @interface StartTetheringError {
+    }
+
+    public static final int TETHER_ERROR_NO_ERROR = 0;
+    public static final int TETHER_ERROR_UNKNOWN_IFACE = 1;
+    public static final int TETHER_ERROR_SERVICE_UNAVAIL = 2;
+    public static final int TETHER_ERROR_UNSUPPORTED = 3;
+    public static final int TETHER_ERROR_UNAVAIL_IFACE = 4;
+    public static final int TETHER_ERROR_INTERNAL_ERROR = 5;
     public static final int TETHER_ERROR_TETHER_IFACE_ERROR = 6;
     public static final int TETHER_ERROR_UNTETHER_IFACE_ERROR = 7;
-    public static final int TETHER_ERROR_ENABLE_NAT_ERROR     = 8;
-    public static final int TETHER_ERROR_DISABLE_NAT_ERROR    = 9;
-    public static final int TETHER_ERROR_IFACE_CFG_ERROR      = 10;
-    public static final int TETHER_ERROR_PROVISION_FAILED     = 11;
-    public static final int TETHER_ERROR_DHCPSERVER_ERROR     = 12;
+    public static final int TETHER_ERROR_ENABLE_FORWARDING_ERROR = 8;
+    public static final int TETHER_ERROR_DISABLE_FORWARDING_ERROR = 9;
+    public static final int TETHER_ERROR_IFACE_CFG_ERROR = 10;
+    public static final int TETHER_ERROR_PROVISIONING_FAILED = 11;
+    public static final int TETHER_ERROR_DHCPSERVER_ERROR = 12;
     public static final int TETHER_ERROR_ENTITLEMENT_UNKNOWN = 13;
     public static final int TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION = 14;
     public static final int TETHER_ERROR_NO_ACCESS_TETHERING_PERMISSION = 15;
+    public static final int TETHER_ERROR_UNKNOWN_TYPE = 16;
 
     /** @hide */
     @Retention(RetentionPolicy.SOURCE)
@@ -508,7 +559,7 @@
             private final TetheringRequestParcel mBuilderParcel;
 
             /** Default constructor of Builder. */
-            public Builder(final int type) {
+            public Builder(@TetheringType final int type) {
                 mBuilderParcel = new TetheringRequestParcel();
                 mBuilderParcel.tetheringType = type;
                 mBuilderParcel.localIPv4Address = null;
@@ -553,11 +604,14 @@
                 return this;
             }
 
-            /** Start tethering without showing the provisioning UI. */
+            /**
+             * If an entitlement check is needed, sets whether to show the entitlement UI or to
+             * perform a silent entitlement check. By default, the entitlement UI is shown.
+             */
             @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED)
             @NonNull
-            public Builder setSilentProvisioning(boolean silent) {
-                mBuilderParcel.showProvisioningUi = silent;
+            public Builder setShouldShowEntitlementUi(boolean showUi) {
+                mBuilderParcel.showProvisioningUi = showUi;
                 return this;
             }
 
@@ -567,7 +621,6 @@
                 return new TetheringRequest(mBuilderParcel);
             }
 
-            /** Get static server address. */
             @Nullable
             public LinkAddress getLocalIpv4Address() {
                 return mBuilderParcel.localIPv4Address;
@@ -578,6 +631,22 @@
             public LinkAddress getClientStaticIpv4Address() {
                 return mBuilderParcel.staticClientAddress;
             }
+
+            /** Get tethering type. */
+            @TetheringType
+            public int getTetheringType() {
+                return mBuilderParcel.tetheringType;
+            }
+
+            /** Check if exempt from entitlement check. */
+            public boolean isExemptFromEntitlementCheck() {
+                return mBuilderParcel.exemptFromEntitlementCheck;
+            }
+
+            /** Check if show entitlement ui.  */
+            public boolean getShouldShowEntitlementUi() {
+                return mBuilderParcel.showProvisioningUi;
+            }
         }
 
         /**
@@ -602,18 +671,18 @@
     /**
      * Callback for use with {@link #startTethering} to find out whether tethering succeeded.
      */
-    public abstract static class StartTetheringCallback {
+    public interface StartTetheringCallback {
         /**
          * Called when tethering has been successfully started.
          */
-        public void onTetheringStarted() {}
+        default void onTetheringStarted() {}
 
         /**
          * Called when starting tethering failed.
          *
-         * @param resultCode One of the {@code TETHER_ERROR_*} constants.
+         * @param error The error that caused the failure.
          */
-        public void onTetheringFailed(final int resultCode) {}
+        default void onTetheringFailed(@StartTetheringError final int error) {}
     }
 
     /**
@@ -684,7 +753,7 @@
             android.Manifest.permission.TETHER_PRIVILEGED,
             android.Manifest.permission.WRITE_SETTINGS
     })
-    public void stopTethering(final int type) {
+    public void stopTethering(@TetheringType final int type) {
         final String callerPkg = mContext.getOpPackageName();
         Log.i(TAG, "stopTethering caller:" + callerPkg);
 
@@ -709,10 +778,10 @@
          *
          * @param resultCode an int value of entitlement result. It may be one of
          *         {@link #TETHER_ERROR_NO_ERROR},
-         *         {@link #TETHER_ERROR_PROVISION_FAILED}, or
+         *         {@link #TETHER_ERROR_PROVISIONING_FAILED}, or
          *         {@link #TETHER_ERROR_ENTITLEMENT_UNKNOWN}.
          */
-        void onTetheringEntitlementResult(int resultCode);
+        void onTetheringEntitlementResult(@EntitlementResult int result);
     }
 
     /**
@@ -727,7 +796,8 @@
      * fail if a tethering entitlement check is required.
      *
      * @param type the downstream type of tethering. Must be one of {@code #TETHERING_*} constants.
-     * @param showEntitlementUi a boolean indicating whether to run UI-based entitlement check.
+     * @param showEntitlementUi a boolean indicating whether to check result for the UI-based
+     *         entitlement check or the silent entitlement check.
      * @param executor the executor on which callback will be invoked.
      * @param listener an {@link OnTetheringEntitlementResultListener} which will be called to
      *         notify the caller of the result of entitlement check. The listener may be called zero
@@ -737,7 +807,8 @@
             android.Manifest.permission.TETHER_PRIVILEGED,
             android.Manifest.permission.WRITE_SETTINGS
     })
-    public void requestLatestTetheringEntitlementResult(int type, boolean showEntitlementUi,
+    public void requestLatestTetheringEntitlementResult(@TetheringType int type,
+            boolean showEntitlementUi,
             @NonNull Executor executor,
             @NonNull final OnTetheringEntitlementResultListener listener) {
         if (listener == null) {
@@ -766,7 +837,7 @@
      */
     // TODO: improve the usage of ResultReceiver, b/145096122
     @SystemApi(client = MODULE_LIBRARIES)
-    public void requestLatestTetheringEntitlementResult(final int type,
+    public void requestLatestTetheringEntitlementResult(@TetheringType final int type,
             @NonNull final ResultReceiver receiver, final boolean showEntitlementUi) {
         final String callerPkg = mContext.getOpPackageName();
         Log.i(TAG, "getLatestTetheringEntitlementResult caller:" + callerPkg);
@@ -779,7 +850,7 @@
      * Callback for use with {@link registerTetheringEventCallback} to find out tethering
      * upstream status.
      */
-    public abstract static class TetheringEventCallback {
+    public interface TetheringEventCallback {
         /**
          * Called when tethering supported status changed.
          *
@@ -791,7 +862,7 @@
          *
          * @param supported The new supported status
          */
-        public void onTetheringSupported(boolean supported) {}
+        default void onTetheringSupported(boolean supported) {}
 
         /**
          * Called when tethering upstream changed.
@@ -802,7 +873,7 @@
          * @param network the {@link Network} of tethering upstream. Null means tethering doesn't
          * have any upstream.
          */
-        public void onUpstreamChanged(@Nullable Network network) {}
+        default void onUpstreamChanged(@Nullable Network network) {}
 
         /**
          * Called when there was a change in tethering interface regular expressions.
@@ -810,28 +881,30 @@
          * <p>This will be called immediately after the callback is registered, and may be called
          * multiple times later upon changes.
          * @param reg The new regular expressions.
-         * @deprecated Referencing interfaces by regular expressions is a deprecated mechanism.
+         *
+         * @hide
          */
-        @Deprecated
-        public void onTetherableInterfaceRegexpsChanged(@NonNull TetheringInterfaceRegexps reg) {}
+        @SystemApi(client = MODULE_LIBRARIES)
+        default void onTetherableInterfaceRegexpsChanged(@NonNull TetheringInterfaceRegexps reg) {}
 
         /**
-         * Called when there was a change in the list of tetherable interfaces.
+         * Called when there was a change in the list of tetherable interfaces. Tetherable
+         * interface means this interface is available and can be used for tethering.
          *
          * <p>This will be called immediately after the callback is registered, and may be called
          * multiple times later upon changes.
-         * @param interfaces The list of tetherable interfaces.
+         * @param interfaces The list of tetherable interface names.
          */
-        public void onTetherableInterfacesChanged(@NonNull List<String> interfaces) {}
+        default void onTetherableInterfacesChanged(@NonNull List<String> interfaces) {}
 
         /**
          * Called when there was a change in the list of tethered interfaces.
          *
          * <p>This will be called immediately after the callback is registered, and may be called
          * multiple times later upon changes.
-         * @param interfaces The list of tethered interfaces.
+         * @param interfaces The list of 0 or more String of currently tethered interface names.
          */
-        public void onTetheredInterfacesChanged(@NonNull List<String> interfaces) {}
+        default void onTetheredInterfacesChanged(@NonNull List<String> interfaces) {}
 
         /**
          * Called when an error occurred configuring tethering.
@@ -841,7 +914,7 @@
          * @param ifName Name of the interface.
          * @param error One of {@code TetheringManager#TETHER_ERROR_*}.
          */
-        public void onError(@NonNull String ifName, int error) {}
+        default void onError(@NonNull String ifName, @TetheringIfaceError int error) {}
 
         /**
          * Called when the list of tethered clients changes.
@@ -854,7 +927,7 @@
          * determine if they are still connected.
          * @param clients The new set of tethered clients; the collection is not ordered.
          */
-        public void onClientsChanged(@NonNull Collection<TetheredClient> clients) {}
+        default void onClientsChanged(@NonNull Collection<TetheredClient> clients) {}
 
         /**
          * Called when tethering offload status changes.
@@ -862,19 +935,20 @@
          * <p>This will be called immediately after the callback is registered.
          * @param status The offload status.
          */
-        public void onOffloadStatusChanged(@TetherOffloadStatus int status) {}
+        default void onOffloadStatusChanged(@TetherOffloadStatus int status) {}
     }
 
     /**
      * Regular expressions used to identify tethering interfaces.
-     * @deprecated Referencing interfaces by regular expressions is a deprecated mechanism.
+     * @hide
      */
-    @Deprecated
+    @SystemApi(client = MODULE_LIBRARIES)
     public static class TetheringInterfaceRegexps {
         private final String[] mTetherableBluetoothRegexs;
         private final String[] mTetherableUsbRegexs;
         private final String[] mTetherableWifiRegexs;
 
+        /** @hide */
         public TetheringInterfaceRegexps(@NonNull String[] tetherableBluetoothRegexs,
                 @NonNull String[] tetherableUsbRegexs, @NonNull String[] tetherableWifiRegexs) {
             mTetherableBluetoothRegexs = tetherableBluetoothRegexs.clone();