diff --git a/api/current.txt b/api/current.txt
index b77d3e6..6b15bb3 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -26011,6 +26011,7 @@
     method public boolean protect(java.net.Socket);
     method public boolean protect(java.net.DatagramSocket);
     method public boolean setUnderlyingNetworks(android.net.Network[]);
+    field public static final java.lang.String METADATA_SUPPORTS_ALWAYS_ON = "android.net.VpnService.SUPPORTS_ALWAYS_ON";
     field public static final java.lang.String SERVICE_INTERFACE = "android.net.VpnService";
   }
 
diff --git a/api/system-current.txt b/api/system-current.txt
index 7bf67fc..820e55e 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -28306,6 +28306,7 @@
     method public boolean protect(java.net.Socket);
     method public boolean protect(java.net.DatagramSocket);
     method public boolean setUnderlyingNetworks(android.net.Network[]);
+    field public static final java.lang.String METADATA_SUPPORTS_ALWAYS_ON = "android.net.VpnService.SUPPORTS_ALWAYS_ON";
     field public static final java.lang.String SERVICE_INTERFACE = "android.net.VpnService";
   }
 
diff --git a/api/test-current.txt b/api/test-current.txt
index f3e4725..d43f5f6 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -26122,6 +26122,7 @@
     method public boolean protect(java.net.Socket);
     method public boolean protect(java.net.DatagramSocket);
     method public boolean setUnderlyingNetworks(android.net.Network[]);
+    field public static final java.lang.String METADATA_SUPPORTS_ALWAYS_ON = "android.net.VpnService.SUPPORTS_ALWAYS_ON";
     field public static final java.lang.String SERVICE_INTERFACE = "android.net.VpnService";
   }
 
diff --git a/core/java/android/app/admin/DevicePolicyManager.java b/core/java/android/app/admin/DevicePolicyManager.java
index c4d22a3..d8da8c5 100644
--- a/core/java/android/app/admin/DevicePolicyManager.java
+++ b/core/java/android/app/admin/DevicePolicyManager.java
@@ -3929,26 +3929,18 @@
 
     /**
      * Called by a device or profile owner to configure an always-on VPN connection through a
-     * specific application for the current user.
-     *
-     * @deprecated this version only exists for compability with previous developer preview builds.
-     *             TODO: delete once there are no longer any live references.
-     * @hide
-     */
-    @Deprecated
-    public void setAlwaysOnVpnPackage(@NonNull ComponentName admin, @Nullable String vpnPackage)
-            throws NameNotFoundException, UnsupportedOperationException {
-        setAlwaysOnVpnPackage(admin, vpnPackage, /* lockdownEnabled */ true);
-    }
-
-    /**
-     * Called by a device or profile owner to configure an always-on VPN connection through a
      * specific application for the current user. This connection is automatically granted and
      * persisted after a reboot.
      * <p>
-     * The designated package should declare a {@link android.net.VpnService} in its manifest
-     * guarded by {@link android.Manifest.permission#BIND_VPN_SERVICE}, otherwise the call will
-     * fail.
+     * To support the always-on feature, an app must
+     * <ul>
+     *     <li>declare a {@link android.net.VpnService} in its manifest, guarded by
+     *         {@link android.Manifest.permission#BIND_VPN_SERVICE};</li>
+     *     <li>target {@link android.os.Build.VERSION_CODES#N API 24} or above; and</li>
+     *     <li><i>not</i> explicitly opt out of the feature through
+     *         {@link android.net.VpnService#METADATA_SUPPORTS_ALWAYS_ON}.</li>
+     * </ul>
+     * The call will fail if called with the package name of an unsupported VPN app.
      *
      * @param vpnPackage The package name for an installed VPN app on the device, or {@code null} to
      *        remove an existing always-on VPN configuration.
diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 7a1d85c..48123fe 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -835,6 +835,29 @@
     }
 
     /**
+     * Checks if a VPN app supports always-on mode.
+     *
+     * In order to support the always-on feature, an app has to
+     * <ul>
+     *     <li>target {@link VERSION_CODES#N API 24} or above, and
+     *     <li>not opt out through the {@link VpnService#METADATA_SUPPORTS_ALWAYS_ON} meta-data
+     *         field.
+     * </ul>
+     *
+     * @param userId The identifier of the user for whom the VPN app is installed.
+     * @param vpnPackage The canonical package name of the VPN app.
+     * @return {@code true} if and only if the VPN app exists and supports always-on mode.
+     * @hide
+     */
+    public boolean isAlwaysOnVpnPackageSupportedForUser(int userId, @Nullable String vpnPackage) {
+        try {
+            return mService.isAlwaysOnVpnPackageSupported(userId, vpnPackage);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
      * Configures an always-on VPN connection through a specific application.
      * This connection is automatically granted and persisted after a reboot.
      *
diff --git a/core/java/android/net/IConnectivityManager.aidl b/core/java/android/net/IConnectivityManager.aidl
index 14cee36..a6fe738 100644
--- a/core/java/android/net/IConnectivityManager.aidl
+++ b/core/java/android/net/IConnectivityManager.aidl
@@ -123,6 +123,7 @@
     VpnInfo[] getAllVpnInfo();
 
     boolean updateLockdownVpn();
+    boolean isAlwaysOnVpnPackageSupported(int userId, String packageName);
     boolean setAlwaysOnVpnPackage(int userId, String packageName, boolean lockdown);
     String getAlwaysOnVpnPackage(int userId);
 
diff --git a/core/java/android/net/VpnService.java b/core/java/android/net/VpnService.java
index 4b79cbb..7fb0c47 100644
--- a/core/java/android/net/VpnService.java
+++ b/core/java/android/net/VpnService.java
@@ -28,8 +28,6 @@
 import android.content.Intent;
 import android.content.pm.IPackageManager;
 import android.content.pm.PackageManager;
-import android.net.Network;
-import android.net.NetworkUtils;
 import android.os.Binder;
 import android.os.IBinder;
 import android.os.Parcel;
@@ -131,6 +129,35 @@
     public static final String SERVICE_INTERFACE = VpnConfig.SERVICE_INTERFACE;
 
     /**
+     * Key for boolean meta-data field indicating whether this VpnService supports always-on mode.
+     *
+     * <p>For a VPN app targeting {@link android.os.Build.VERSION_CODES#N API 24} or above, Android
+     * provides users with the ability to set it as always-on, so that VPN connection is
+     * persisted after device reboot and app upgrade. Always-on VPN can also be enabled by device
+     * owner and profile owner apps through
+     * {@link android.app.admin.DevicePolicyManager#setAlwaysOnVpnPackage}.
+     *
+     * <p>VPN apps not supporting this feature should opt out by adding this meta-data field to the
+     * {@code VpnService} component of {@code AndroidManifest.xml}. In case there is more than one
+     * {@code VpnService} component defined in {@code AndroidManifest.xml}, opting out any one of
+     * them will opt out the entire app. For example,
+     * <pre> {@code
+     * <service android:name=".ExampleVpnService"
+     *         android:permission="android.permission.BIND_VPN_SERVICE">
+     *     <intent-filter>
+     *         <action android:name="android.net.VpnService"/>
+     *     </intent-filter>
+     *     <meta-data android:name="android.net.VpnService.SUPPORTS_ALWAYS_ON"
+     *             android:value=false/>
+     * </service>
+     * } </pre>
+     *
+     * <p>This meta-data field defaults to {@code true} if absent.
+     */
+    public static final String METADATA_SUPPORTS_ALWAYS_ON =
+            "android.net.VpnService.SUPPORTS_ALWAYS_ON";
+
+    /**
      * Use IConnectivityManager since those methods are hidden and not
      * available in ConnectivityManager.
      */
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 8200289..71c423c 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -40,7 +40,6 @@
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
-import android.content.pm.PackageManager;
 import android.content.res.Configuration;
 import android.database.ContentObserver;
 import android.net.ConnectivityManager;
@@ -52,10 +51,10 @@
 import android.net.INetworkStatsService;
 import android.net.LinkProperties;
 import android.net.LinkProperties.CompareResult;
+import android.net.MatchAllNetworkSpecifier;
 import android.net.Network;
 import android.net.NetworkAgent;
 import android.net.NetworkCapabilities;
-import android.net.MatchAllNetworkSpecifier;
 import android.net.NetworkConfig;
 import android.net.NetworkInfo;
 import android.net.NetworkInfo.DetailedState;
@@ -124,13 +123,12 @@
 import com.android.internal.util.MessageUtils;
 import com.android.internal.util.WakeupMessage;
 import com.android.internal.util.XmlUtils;
-import com.android.server.LocalServices;
 import com.android.server.am.BatteryStatsService;
 import com.android.server.connectivity.DataConnectionStats;
 import com.android.server.connectivity.KeepaliveTracker;
+import com.android.server.connectivity.LingerMonitor;
 import com.android.server.connectivity.MockableSystemProperties;
 import com.android.server.connectivity.Nat464Xlat;
-import com.android.server.connectivity.LingerMonitor;
 import com.android.server.connectivity.NetworkAgentInfo;
 import com.android.server.connectivity.NetworkDiagnostics;
 import com.android.server.connectivity.NetworkMonitor;
@@ -139,8 +137,8 @@
 import com.android.server.connectivity.PacManager;
 import com.android.server.connectivity.PermissionMonitor;
 import com.android.server.connectivity.Tethering;
-import com.android.server.connectivity.tethering.TetheringDependencies;
 import com.android.server.connectivity.Vpn;
+import com.android.server.connectivity.tethering.TetheringDependencies;
 import com.android.server.net.BaseNetworkObserver;
 import com.android.server.net.LockdownVpnTracker;
 import com.android.server.net.NetworkPolicyManagerInternal;
@@ -1494,6 +1492,12 @@
         ConnectivityManager.enforceChangePermission(mContext);
     }
 
+    private void enforceSettingsPermission() {
+        mContext.enforceCallingOrSelfPermission(
+                android.Manifest.permission.NETWORK_SETTINGS,
+                "ConnectivityService");
+    }
+
     private void enforceTetherAccessPermission() {
         mContext.enforceCallingOrSelfPermission(
                 android.Manifest.permission.ACCESS_NETWORK_STATE,
@@ -3625,6 +3629,21 @@
     }
 
     @Override
+    public boolean isAlwaysOnVpnPackageSupported(int userId, String packageName) {
+        enforceSettingsPermission();
+        enforceCrossUserPermission(userId);
+
+        synchronized (mVpns) {
+            Vpn vpn = mVpns.get(userId);
+            if (vpn == null) {
+                Slog.w(TAG, "User " + userId + " has no Vpn configuration");
+                return false;
+            }
+            return vpn.isAlwaysOnPackageSupported(packageName);
+        }
+    }
+
+    @Override
     public boolean setAlwaysOnVpnPackage(int userId, String packageName, boolean lockdown) {
         enforceConnectivityInternalPermission();
         enforceCrossUserPermission(userId);
diff --git a/services/core/java/com/android/server/connectivity/Vpn.java b/services/core/java/com/android/server/connectivity/Vpn.java
index 27968a9..e82eabf 100644
--- a/services/core/java/com/android/server/connectivity/Vpn.java
+++ b/services/core/java/com/android/server/connectivity/Vpn.java
@@ -36,6 +36,7 @@
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.ServiceConnection;
+import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
 import android.content.pm.ResolveInfo;
@@ -56,7 +57,10 @@
 import android.net.RouteInfo;
 import android.net.UidRange;
 import android.net.Uri;
+import android.net.VpnService;
 import android.os.Binder;
+import android.os.Build.VERSION_CODES;
+import android.os.Bundle;
 import android.os.FileUtils;
 import android.os.IBinder;
 import android.os.INetworkManagementService;
@@ -296,6 +300,56 @@
     }
 
     /**
+     * Checks if a VPN app supports always-on mode.
+     *
+     * In order to support the always-on feature, an app has to
+     * <ul>
+     *     <li>target {@link VERSION_CODES#N API 24} or above, and
+     *     <li>not opt out through the {@link VpnService#METADATA_SUPPORTS_ALWAYS_ON} meta-data
+     *         field.
+     * </ul>
+     *
+     * @param packageName the canonical package name of the VPN app
+     * @return {@code true} if and only if the VPN app exists and supports always-on mode
+     */
+    public boolean isAlwaysOnPackageSupported(String packageName) {
+        enforceSettingsPermission();
+
+        if (packageName == null) {
+            return false;
+        }
+
+        PackageManager pm = mContext.getPackageManager();
+        ApplicationInfo appInfo = null;
+        try {
+            appInfo = pm.getApplicationInfoAsUser(packageName, 0 /*flags*/, mUserHandle);
+        } catch (NameNotFoundException unused) {
+            Log.w(TAG, "Can't find \"" + packageName + "\" when checking always-on support");
+        }
+        if (appInfo == null || appInfo.targetSdkVersion < VERSION_CODES.N) {
+            return false;
+        }
+
+        final Intent intent = new Intent(VpnConfig.SERVICE_INTERFACE);
+        intent.setPackage(packageName);
+        List<ResolveInfo> services =
+                pm.queryIntentServicesAsUser(intent, PackageManager.GET_META_DATA, mUserHandle);
+        if (services == null || services.size() == 0) {
+            return false;
+        }
+
+        for (ResolveInfo rInfo : services) {
+            final Bundle metaData = rInfo.serviceInfo.metaData;
+            if (metaData != null
+                    && !metaData.getBoolean(VpnService.METADATA_SUPPORTS_ALWAYS_ON, true)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    /**
      * Configures an always-on VPN connection through a specific application.
      * This connection is automatically granted and persisted after a reboot.
      *
@@ -303,6 +357,10 @@
      *    manifest guarded by {@link android.Manifest.permission.BIND_VPN_SERVICE},
      *    otherwise the call will fail.
      *
+     * <p>Note that this method does not check if the VPN app supports always-on mode. The check is
+     *    delayed to {@link #startAlwaysOnVpn()}, which is always called immediately after this
+     *    method in {@link android.net.IConnectivityManager#setAlwaysOnVpnPackage}.
+     *
      * @param packageName the package to designate as always-on VPN supplier.
      * @param lockdown whether to prevent traffic outside of a VPN, for example while connecting.
      * @return {@code true} if the package has been set as always-on, {@code false} otherwise.
@@ -443,6 +501,11 @@
             if (alwaysOnPackage == null) {
                 return true;
             }
+            // Remove always-on VPN if it's not supported.
+            if (!isAlwaysOnPackageSupported(alwaysOnPackage)) {
+                setAlwaysOnPackage(null, false);
+                return false;
+            }
             // Skip if the service is already established. This isn't bulletproof: it's not bound
             // until after establish(), so if it's mid-setup onStartCommand will be sent twice,
             // which may restart the connection.
@@ -1219,6 +1282,11 @@
                 "Unauthorized Caller");
     }
 
+    private void enforceSettingsPermission() {
+        mContext.enforceCallingOrSelfPermission(Manifest.permission.NETWORK_SETTINGS,
+                "Unauthorized Caller");
+    }
+
     private class Connection implements ServiceConnection {
         private IBinder mService;
 
diff --git a/tests/net/java/com/android/server/connectivity/VpnTest.java b/tests/net/java/com/android/server/connectivity/VpnTest.java
index 506d9e5..f0b3724 100644
--- a/tests/net/java/com/android/server/connectivity/VpnTest.java
+++ b/tests/net/java/com/android/server/connectivity/VpnTest.java
@@ -27,13 +27,16 @@
 import android.app.AppOpsManager;
 import android.app.NotificationManager;
 import android.content.Context;
-import android.content.Intent;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
+import android.content.pm.ResolveInfo;
+import android.content.pm.ServiceInfo;
 import android.content.pm.UserInfo;
 import android.net.NetworkInfo.DetailedState;
 import android.net.UidRange;
-import android.os.Build;
+import android.net.VpnService;
+import android.os.Build.VERSION_CODES;
+import android.os.Bundle;
 import android.os.INetworkManagementService;
 import android.os.Looper;
 import android.os.UserHandle;
@@ -45,22 +48,22 @@
 
 import com.android.internal.net.VpnConfig;
 
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Map;
-import java.util.Set;
-
 import org.mockito.Answers;
-import org.mockito.ArgumentCaptor;
 import org.mockito.InOrder;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Map;
+import java.util.Set;
+
 /**
  * Tests for {@link Vpn}.
  *
  * Build, install and run with:
- *  runtest --path src/com/android/server/connectivity/VpnTest.java
+ *  runtest --path java/com/android/server/connectivity/VpnTest.java
  */
 public class VpnTest extends AndroidTestCase {
     private static final String TAG = "VpnTest";
@@ -116,7 +119,7 @@
 
         // Used by {@link Notification.Builder}
         ApplicationInfo applicationInfo = new ApplicationInfo();
-        applicationInfo.targetSdkVersion = Build.VERSION_CODES.CUR_DEVELOPMENT;
+        applicationInfo.targetSdkVersion = VERSION_CODES.CUR_DEVELOPMENT;
         when(mContext.getApplicationInfo()).thenReturn(applicationInfo);
 
         doNothing().when(mNetService).registerObserver(any());
@@ -315,6 +318,40 @@
     }
 
     @SmallTest
+    public void testIsAlwaysOnPackageSupported() throws Exception {
+        final Vpn vpn = createVpn(primaryUser.id);
+
+        ApplicationInfo appInfo = new ApplicationInfo();
+        when(mPackageManager.getApplicationInfoAsUser(eq(PKGS[0]), anyInt(), eq(primaryUser.id)))
+                .thenReturn(appInfo);
+
+        ServiceInfo svcInfo = new ServiceInfo();
+        ResolveInfo resInfo = new ResolveInfo();
+        resInfo.serviceInfo = svcInfo;
+        when(mPackageManager.queryIntentServicesAsUser(any(), eq(PackageManager.GET_META_DATA),
+                eq(primaryUser.id)))
+                .thenReturn(Collections.singletonList(resInfo));
+
+        // null package name should return false
+        assertFalse(vpn.isAlwaysOnPackageSupported(null));
+
+        // Pre-N apps are not supported
+        appInfo.targetSdkVersion = VERSION_CODES.M;
+        assertFalse(vpn.isAlwaysOnPackageSupported(PKGS[0]));
+
+        // N+ apps are supported by default
+        appInfo.targetSdkVersion = VERSION_CODES.N;
+        assertTrue(vpn.isAlwaysOnPackageSupported(PKGS[0]));
+
+        // Apps that opt out explicitly are not supported
+        appInfo.targetSdkVersion = VERSION_CODES.CUR_DEVELOPMENT;
+        Bundle metaData = new Bundle();
+        metaData.putBoolean(VpnService.METADATA_SUPPORTS_ALWAYS_ON, false);
+        svcInfo.metaData = metaData;
+        assertFalse(vpn.isAlwaysOnPackageSupported(PKGS[0]));
+    }
+
+    @SmallTest
     public void testNotificationShownForAlwaysOnApp() {
         final UserHandle userHandle = UserHandle.of(primaryUser.id);
         final Vpn vpn = createVpn(primaryUser.id);