diff --git a/api/system-current.txt b/api/system-current.txt
index d95eaded32b6b..5b1d6690c72bd 100755
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -9282,6 +9282,7 @@ package android.provider {
     field public static final String DATA_CODING_SCHEME = "dcs";
     field public static final String DEFAULT_SORT_ORDER = "date DESC";
     field public static final String DELIVERY_TIME = "date";
+    field public static final String ETWS_IS_PRIMARY = "etws_is_primary";
     field public static final String ETWS_WARNING_TYPE = "etws_warning_type";
     field public static final String GEOGRAPHICAL_SCOPE = "geo_scope";
     field public static final String GEOMETRIES = "geometries";
diff --git a/api/test-current.txt b/api/test-current.txt
index 86f908bfa8bfe..dc02788098e19 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -3208,6 +3208,7 @@ package android.provider {
     field public static final String DATA_CODING_SCHEME = "dcs";
     field public static final String DEFAULT_SORT_ORDER = "date DESC";
     field public static final String DELIVERY_TIME = "date";
+    field public static final String ETWS_IS_PRIMARY = "etws_is_primary";
     field public static final String ETWS_WARNING_TYPE = "etws_warning_type";
     field public static final String GEOGRAPHICAL_SCOPE = "geo_scope";
     field public static final String GEOMETRIES = "geometries";
diff --git a/core/java/android/provider/Telephony.java b/core/java/android/provider/Telephony.java
index a2489b9b68d9d..4c9afcf5cd057 100644
--- a/core/java/android/provider/Telephony.java
+++ b/core/java/android/provider/Telephony.java
@@ -4325,11 +4325,13 @@ public final class Telephony {
         public static final String ETWS_WARNING_TYPE = "etws_warning_type";
 
         /**
-         * ETWS (Earthquake and Tsunami Warning System) primary message or not (ETWS alerts only).
+         * ETWS (Earthquake and Tsunami Warning System, Japan only) primary message or not. The
+         * primary message is sent as soon as the emergency occurs. It does not provide any
+         * information except the emergency type (e.g. earthquake, tsunami). The ETWS secondary
+         * message is sent afterwards and provides the details of the emergency.
+         *
          * <p>See {@link android.telephony.SmsCbEtwsInfo}</p>
          * <P>Type: BOOLEAN</P>
-         *
-         * @hide        // TODO: Unhide this for S.
          */
         public static final String ETWS_IS_PRIMARY = "etws_is_primary";
 
diff --git a/non-updatable-api/system-current.txt b/non-updatable-api/system-current.txt
index b9e463cc017ef..9dac11876ce3e 100644
--- a/non-updatable-api/system-current.txt
+++ b/non-updatable-api/system-current.txt
@@ -8156,6 +8156,7 @@ package android.provider {
     field public static final String DATA_CODING_SCHEME = "dcs";
     field public static final String DEFAULT_SORT_ORDER = "date DESC";
     field public static final String DELIVERY_TIME = "date";
+    field public static final String ETWS_IS_PRIMARY = "etws_is_primary";
     field public static final String ETWS_WARNING_TYPE = "etws_warning_type";
     field public static final String GEOGRAPHICAL_SCOPE = "geo_scope";
     field public static final String GEOMETRIES = "geometries";