--- a/mobile/android/app/src/test/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetrySyncPingBuilderTest.java
+++ b/mobile/android/app/src/test/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetrySyncPingBuilderTest.java
@@ -11,18 +11,16 @@ import org.json.JSONException;
 import org.json.simple.JSONArray;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mozilla.gecko.background.testhelpers.TestRunner;
 import org.mozilla.gecko.sync.ExtendedJSONObject;
 import org.mozilla.gecko.sync.synchronizer.StoreBatchTracker;
 import org.mozilla.gecko.sync.telemetry.TelemetryStageCollector;
-import org.mozilla.gecko.sync.validation.BookmarkValidationResults;
-import org.mozilla.gecko.sync.validation.ValidationResults;
 import org.mozilla.gecko.telemetry.TelemetryLocalPing;
 
 import java.util.ArrayList;
 import java.util.HashMap;
 
 import static org.junit.Assert.*;
 
 @RunWith(TestRunner.class)
@@ -34,37 +32,29 @@ public class TelemetrySyncPingBuilderTes
     public void setUp() throws Exception {
         pingStore = new TelemetrySyncPingBundleBuilderTest.MockTelemetryPingStore();
         builder = new TelemetrySyncPingBuilder();
     }
 
     @Test
     public void testGeneralShape() throws Exception {
         TelemetryLocalPing localPing = builder
-                .setDeviceID("device-id")
-                .setUID("uid")
                 .setTook(123L)
                 .setRestarted(false)
                 .build();
         ExtendedJSONObject payload = localPing.getPayload();
-        assertEquals("uid", payload.getString("uid"));
         assertEquals(Long.valueOf(123L), payload.getLong("took"));
-        assertEquals("device-id", payload.getString("deviceID"));
         assertFalse(payload.containsKey("restarted"));
 
         localPing = builder
-                .setDeviceID("device-id")
-                .setUID("uid")
                 .setTook(123L)
                 .setRestarted(true)
                 .build();
         payload = localPing.getPayload();
-        assertEquals("uid", payload.getString("uid"));
         assertEquals(Long.valueOf(123L), payload.getLong("took"));
-        assertEquals("device-id", payload.getString("deviceID"));
         assertTrue(payload.getLong("when") != null);
         assertEquals(true, payload.getBoolean("restarted"));
 
     }
 
     @Test
     public void testStage() throws Exception {
         HashMap<String, TelemetryStageCollector> stages = new HashMap<>();

--- a/mobile/android/app/src/test/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetrySyncPingBundleBuilderTest.java
+++ b/mobile/android/app/src/test/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetrySyncPingBundleBuilderTest.java
@@ -100,16 +100,18 @@ public class TelemetrySyncPingBundleBuil
         syncPings = new MockTelemetryPingStore();
         eventPings = new MockTelemetryPingStore();
     }
 
     @Test
     public void testGeneralShape() throws Exception {
         builder.setSyncStore(syncPings);
         builder.setSyncEventStore(eventPings);
+        builder.setDeviceID("device-id-1");
+        builder.setUID("uid-1");
 
         TelemetryOutgoingPing outgoingPing = builder.build();
 
         assertTrue(outgoingPing.getPayload().containsKey("application"));
         assertTrue(outgoingPing.getPayload().containsKey("payload"));
         assertTrue(outgoingPing.getPayload().containsKey("id"));
         assertEquals("sync", outgoingPing.getPayload().getString("type"));
         assertEquals(Integer.valueOf(4), outgoingPing.getPayload().getIntegerSafely("version"));
@@ -123,80 +125,77 @@ public class TelemetrySyncPingBundleBuil
         assertTrue(application.containsKey("version"));
         assertTrue(application.containsKey("name"));
         assertTrue(application.containsKey("channel"));
         assertTrue(application.containsKey("buildId"));
         assertTrue(application.containsKey("xpcomAbi"));
 
 
         // Test general shape of payload. Expecting {"syncs":[],"why":"schedule", "version": 1,
-        // "os": {"name": "Android", "version": "<version>", "locale": "<locale>"}}.
+        // "os": {"name": "Android", "version": "<version>", "locale": "<locale>"},
+        // "deviceID": <Hashed Device ID>, "uid": <Hashed UID>}.
         // NB that even though we set an empty sync event store, it's not in the json string.
         // That's because sync events are not yet instrumented.
         ExtendedJSONObject payload = outgoingPing.getPayload().getObject("payload");
-        assertEquals(4, payload.keySet().size());
+        assertEquals(6, payload.keySet().size());
         assertEquals("schedule", payload.getString("why"));
         assertEquals(Integer.valueOf(1), payload.getIntegerSafely("version"));
+        assertEquals(payload.getString("uid"), "uid-1");
+        assertEquals(payload.getString("deviceID"), "device-id-1");
         assertEquals(0, payload.getArray("syncs").size());
         // Test os key.
         ExtendedJSONObject os = payload.getObject("os");
         assertEquals(3, os.keySet().size());
         assertEquals("Android", os.getString("name"));
         // Going to be different depending on the test environment.
         // Test for presence and type to void random failures.
         assertTrue(os.getIntegerSafely("version") != null);
         // Likely "en-US" in tests, but let's test for presence and type to avoid random failures.
         assertTrue(os.getString("locale") != null);
     }
 
     @Test
     public void testBundlingOfMultiplePings() throws Exception {
         // Try just one ping first.
         syncPings.storePing(new TelemetrySyncPingBuilder()
-                .setDeviceID("test-device-id")
                 .setRestarted(true)
                 .setTook(123L)
-                .setUID("test-uid")
                 .build()
         );
         builder.setSyncStore(syncPings);
 
         TelemetryOutgoingPing outgoingPing = builder.build();
 
         // Ensure we have that one ping.
         ExtendedJSONObject payload = outgoingPing.getPayload().getObject("payload");
         assertEquals("schedule", payload.getString("why"));
         JSONArray syncs = payload.getArray("syncs");
         assertEquals(1, syncs.size());
-        assertSync((ExtendedJSONObject) syncs.get(0), "test-uid", 123L, "test-device-id", true);
+        assertSync((ExtendedJSONObject) syncs.get(0), 123L, true);
 
         // Add another ping.
         syncPings.storePing(new TelemetrySyncPingBuilder()
-                .setDeviceID("test-device-id")
                 .setRestarted(false)
                 .setTook(321L)
-                .setUID("test-uid")
                 .build()
         );
         builder.setSyncStore(syncPings);
 
         // We should have two pings now.
         outgoingPing = builder.build();
         syncs = outgoingPing.getPayload()
                 .getObject("payload")
                 .getArray("syncs");
         assertEquals(2, syncs.size());
-        assertSync((ExtendedJSONObject) syncs.get(0), "test-uid", 123L, "test-device-id", true);
-        assertSync((ExtendedJSONObject) syncs.get(1), "test-uid", 321L, "test-device-id", false);
+        assertSync((ExtendedJSONObject) syncs.get(0), 123L, true);
+        assertSync((ExtendedJSONObject) syncs.get(1), 321L, false);
     }
 
-    private void assertSync(ExtendedJSONObject sync, String uid, long took, String deviceID, boolean restarted) throws JSONException {
-        assertEquals(uid, sync.getString("uid"));
+    private void assertSync(ExtendedJSONObject sync, long took, boolean restarted) throws JSONException {
         assertEquals(Long.valueOf(took), sync.getLong("took"));
-        assertEquals(deviceID, sync.getString("deviceID"));
 
         // Test that 'when' timestamp looks generally sane.
         final long now = System.currentTimeMillis();
         final long yearAgo = now - 1000L * 60 * 60 * 24 * 365;
         assertTrue(sync.getLong("when") > yearAgo);
         assertTrue(sync.getLong("when") <= now);
 
         if (restarted) {

--- a/mobile/android/base/java/org/mozilla/gecko/telemetry/TelemetryBackgroundReceiver.java
+++ b/mobile/android/base/java/org/mozilla/gecko/telemetry/TelemetryBackgroundReceiver.java
@@ -146,24 +146,16 @@ public class TelemetryBackgroundReceiver
                         final Serializable error = telemetryBundle.getSerializable(TelemetryContract.KEY_ERROR);
                         final Serializable stages = telemetryBundle.getSerializable(TelemetryContract.KEY_STAGES);
                         final long took = telemetryBundle.getLong(TelemetryContract.KEY_TOOK);
                         final boolean didRestart = telemetryBundle.getBoolean(TelemetryContract.KEY_RESTARTED);
 
                         telemetryStore = syncTelemetryStore;
                         TelemetrySyncPingBuilder localPingBuilder = new TelemetrySyncPingBuilder();
 
-                        if (uid != null) {
-                            localPingBuilder.setUID(uid);
-                        }
-
-                        if (deviceID != null) {
-                            localPingBuilder.setDeviceID(deviceID);
-                        }
-
                         if (devices != null) {
                             localPingBuilder.setDevices(devices);
                         }
 
                         if (stages != null) {
                             localPingBuilder.setStages(stages);
                         }
 
@@ -228,16 +220,18 @@ public class TelemetryBackgroundReceiver
                     // we're processing the current telemetry.
                     // Chances of that happening are very small due to how often background telemetry
                     // is actually emitted: very infrequently on a timescale of disk access.
                     final Set<String> localSyncTelemetryToRemove = syncTelemetryStore.getStoredIDs();
                     final Set<String> localSyncEventTelemetryToRemove = syncEventTelemetryStore.getStoredIDs();
 
                     // Bundle up all that we have in our telemetry stores.
                     final TelemetryOutgoingPing syncPing = new TelemetrySyncPingBundleBuilder()
+                            .setUID(uid)
+                            .setDeviceID(deviceID)
                             .setSyncStore(syncTelemetryStore)
                             .setSyncEventStore(syncEventTelemetryStore)
                             .setReason(reasonToUpload)
                             .build();
 
                     // Persist a Sync Ping Bundle.
                     boolean bundledSyncPingPersisted = true;
                     try {

--- a/mobile/android/base/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetrySyncPingBuilder.java
+++ b/mobile/android/base/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetrySyncPingBuilder.java
@@ -84,26 +84,16 @@ public class TelemetrySyncPingBuilder ex
             }
 
             addUnchecked(engines, stageJSON);
         }
         payload.put("engines", engines);
         return this;
     }
 
-    public TelemetrySyncPingBuilder setUID(@NonNull String uid) {
-        payload.put("uid", uid);
-        return this;
-    }
-
-    public TelemetrySyncPingBuilder setDeviceID(@NonNull String deviceID) {
-        payload.put("deviceID", deviceID);
-        return this;
-    }
-
     @Nullable
     private static JSONArray buildOutgoing(List<StoreBatchTracker.Batch> batches) {
         if (batches == null || batches.size() == 0) {
             return null;
         }
         JSONArray arr = new JSONArray();
         for (int i = 0; i < batches.size(); ++i) {
             StoreBatchTracker.Batch batch = batches.get(i);

--- a/mobile/android/base/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetrySyncPingBundleBuilder.java
+++ b/mobile/android/base/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetrySyncPingBundleBuilder.java
@@ -64,16 +64,26 @@ public class TelemetrySyncPingBundleBuil
         return new String[0];
     }
 
     public TelemetrySyncPingBundleBuilder setReason(@NonNull String reason) {
         pingData.put("why", reason);
         return this;
     }
 
+    public TelemetrySyncPingBundleBuilder setUID(@NonNull String uid) {
+        pingData.put("uid", uid);
+        return this;
+    }
+
+    public TelemetrySyncPingBundleBuilder setDeviceID(@NonNull String deviceID) {
+        pingData.put("deviceID", deviceID);
+        return this;
+    }
+
     @Override
     public TelemetryOutgoingPing build() {
         final DateFormat pingCreationDateFormat = new SimpleDateFormat(
                 "yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.US);
         pingCreationDateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
 
         payload.put("type", PING_TYPE);
         payload.put("version", PING_BUNDLE_VERSION);