diff --git a/api/system-current.txt b/api/system-current.txt
index 5bac2b7..b674e92 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -9446,17 +9446,17 @@
 
   public class ImsSmsImplBase {
     ctor public ImsSmsImplBase();
-    method public void acknowledgeSms(int, int, int);
-    method public void acknowledgeSmsReport(int, int, int);
+    method public void acknowledgeSms(int, @IntRange(from=0, to=65535) int, int);
+    method public void acknowledgeSmsReport(int, @IntRange(from=0, to=65535) int, int);
     method public String getSmsFormat();
     method public void onReady();
-    method @Deprecated public final void onSendSmsResult(int, int, int, int) throws java.lang.RuntimeException;
-    method public final void onSendSmsResultError(int, int, int, int, int) throws java.lang.RuntimeException;
-    method public final void onSendSmsResultSuccess(int, int) throws java.lang.RuntimeException;
+    method @Deprecated public final void onSendSmsResult(int, @IntRange(from=0, to=65535) int, int, int) throws java.lang.RuntimeException;
+    method public final void onSendSmsResultError(int, @IntRange(from=0, to=65535) int, int, int, int) throws java.lang.RuntimeException;
+    method public final void onSendSmsResultSuccess(int, @IntRange(from=0, to=65535) int) throws java.lang.RuntimeException;
     method public final void onSmsReceived(int, String, byte[]) throws java.lang.RuntimeException;
-    method @Deprecated public final void onSmsStatusReportReceived(int, int, String, byte[]) throws java.lang.RuntimeException;
+    method @Deprecated public final void onSmsStatusReportReceived(int, @IntRange(from=0, to=65535) int, String, byte[]) throws java.lang.RuntimeException;
     method public final void onSmsStatusReportReceived(int, String, byte[]) throws java.lang.RuntimeException;
-    method public void sendSms(int, int, String, String, boolean, byte[]);
+    method public void sendSms(int, @IntRange(from=0, to=65535) int, String, String, boolean, byte[]);
     field public static final int DELIVER_STATUS_ERROR_GENERIC = 2; // 0x2
     field public static final int DELIVER_STATUS_ERROR_NO_MEMORY = 3; // 0x3
     field public static final int DELIVER_STATUS_ERROR_REQUEST_NOT_SUPPORTED = 4; // 0x4
diff --git a/telephony/java/android/telephony/SmsManager.java b/telephony/java/android/telephony/SmsManager.java
index 8c14cb4..209d462 100644
--- a/telephony/java/android/telephony/SmsManager.java
+++ b/telephony/java/android/telephony/SmsManager.java
@@ -2021,6 +2021,36 @@
 
     // SMS send failure result codes
 
+    /** @hide */
+    @IntDef(prefix = { "RESULT" }, value = {
+            RESULT_ERROR_NONE,
+            RESULT_ERROR_GENERIC_FAILURE,
+            RESULT_ERROR_RADIO_OFF,
+            RESULT_ERROR_NULL_PDU,
+            RESULT_ERROR_NO_SERVICE,
+            RESULT_ERROR_LIMIT_EXCEEDED,
+            RESULT_ERROR_FDN_CHECK_FAILURE,
+            RESULT_ERROR_SHORT_CODE_NOT_ALLOWED,
+            RESULT_ERROR_SHORT_CODE_NEVER_ALLOWED,
+            RESULT_RADIO_NOT_AVAILABLE,
+            RESULT_NETWORK_REJECT,
+            RESULT_INVALID_ARGUMENTS,
+            RESULT_INVALID_STATE,
+            RESULT_NO_MEMORY,
+            RESULT_INVALID_SMS_FORMAT,
+            RESULT_SYSTEM_ERROR,
+            RESULT_MODEM_ERROR,
+            RESULT_NETWORK_ERROR,
+            RESULT_INVALID_SMSC_ADDRESS,
+            RESULT_OPERATION_NOT_ALLOWED,
+            RESULT_INTERNAL_ERROR,
+            RESULT_NO_RESOURCES,
+            RESULT_CANCELLED,
+            RESULT_REQUEST_NOT_SUPPORTED
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface Result {}
+
     /**
      * No error.
      * @hide
diff --git a/telephony/java/android/telephony/ims/stub/ImsSmsImplBase.java b/telephony/java/android/telephony/ims/stub/ImsSmsImplBase.java
index 175769b..36ece95 100644
--- a/telephony/java/android/telephony/ims/stub/ImsSmsImplBase.java
+++ b/telephony/java/android/telephony/ims/stub/ImsSmsImplBase.java
@@ -17,6 +17,7 @@
 package android.telephony.ims.stub;
 
 import android.annotation.IntDef;
+import android.annotation.IntRange;
 import android.annotation.SystemApi;
 import android.os.RemoteException;
 import android.telephony.SmsManager;
@@ -148,14 +149,16 @@
      *
      * @param token unique token generated by the platform that should be used when triggering
      *             callbacks for this specific message.
-     * @param messageRef the message reference.
-     * @param format the format of the message. Valid values are {@link SmsMessage#FORMAT_3GPP} and
-     *               {@link SmsMessage#FORMAT_3GPP2}.
+     * @param messageRef the message reference, which may be 1 byte if it is in
+     *     {@link SmsMessage#FORMAT_3GPP} format (see TS.123.040) or 2 bytes if it is in
+     *     {@link SmsMessage#FORMAT_3GPP2} format (see 3GPP2 C.S0015-B).
+     * @param format the format of the message.
      * @param smsc the Short Message Service Center address.
      * @param isRetry whether it is a retry of an already attempted message or not.
      * @param pdu PDU representing the contents of the message.
      */
-    public void sendSms(int token, int messageRef, String format, String smsc, boolean isRetry,
+    public void sendSms(int token, @IntRange(from = 0, to = 65535) int messageRef,
+            @SmsMessage.Format String format, String smsc, boolean isRetry,
             byte[] pdu) {
         // Base implementation returns error. Should be overridden.
         try {
@@ -172,14 +175,13 @@
      * provider.
      *
      * @param token token provided in {@link #onSmsReceived(int, String, byte[])}
-     * @param messageRef the message reference
-     * @param result result of delivering the message. Valid values are:
-     *  {@link #DELIVER_STATUS_OK},
-     *  {@link #DELIVER_STATUS_ERROR_GENERIC},
-     *  {@link #DELIVER_STATUS_ERROR_NO_MEMORY},
-     *  {@link #DELIVER_STATUS_ERROR_REQUEST_NOT_SUPPORTED}
+     * @param messageRef the message reference, which may be 1 byte if it is in
+     *     {@link SmsMessage#FORMAT_3GPP} format (see TS.123.040) or 2 bytes if it is in
+     *     {@link SmsMessage#FORMAT_3GPP2} format (see 3GPP2 C.S0015-B).
+     * @param result result of delivering the message.
      */
-    public void acknowledgeSms(int token, int messageRef, @DeliverStatusResult int result) {
+    public void acknowledgeSms(int token, @IntRange(from = 0, to = 65535)  int messageRef,
+            @DeliverStatusResult int result) {
         Log.e(LOG_TAG, "acknowledgeSms() not implemented.");
     }
 
@@ -191,12 +193,13 @@
      *
      * @param token token provided in {@link #onSmsStatusReportReceived(int, int, String, byte[])}
      *              or {@link #onSmsStatusReportReceived(int, String, byte[])}
-     * @param messageRef the message reference
-     * @param result result of delivering the message. Valid values are:
-     *  {@link #STATUS_REPORT_STATUS_OK},
-     *  {@link #STATUS_REPORT_STATUS_ERROR}
+     * @param messageRef the message reference, which may be 1 byte if it is in
+     *     {@link SmsMessage#FORMAT_3GPP} format (see TS.123.040) or 2 bytes if it is in
+     *     {@link SmsMessage#FORMAT_3GPP2} format (see 3GPP2 C.S0015-B).
+     * @param result result of delivering the message.
      */
-    public void acknowledgeSmsReport(int token, int messageRef, @StatusReportResult int result) {
+    public void acknowledgeSmsReport(int token, @IntRange(from = 0, to = 65535) int messageRef,
+            @StatusReportResult int result) {
         Log.e(LOG_TAG, "acknowledgeSmsReport() not implemented.");
     }
 
@@ -210,12 +213,12 @@
      * {@link #DELIVER_STATUS_ERROR_GENERIC} result code.
      * @param token unique token generated by IMS providers that the platform will use to trigger
      *              callbacks for this message.
-     * @param format the format of the message. Valid values are {@link SmsMessage#FORMAT_3GPP} and
-     * {@link SmsMessage#FORMAT_3GPP2}.
+     * @param format the format of the message.
      * @param pdu PDU representing the contents of the message.
      * @throws RuntimeException if called before {@link #onReady()} is triggered.
      */
-    public final void onSmsReceived(int token, String format, byte[] pdu) throws RuntimeException {
+    public final void onSmsReceived(int token, @SmsMessage.Format String format, byte[] pdu)
+            throws RuntimeException {
         synchronized (mLock) {
             if (mListener == null) {
                 throw new RuntimeException("Feature not ready.");
@@ -241,13 +244,16 @@
      * sent successfully.
      *
      * @param token token provided in {@link #sendSms(int, int, String, String, boolean, byte[])}
-     * @param messageRef the message reference. Should be between 0 and 255 per TS.123.040
+     * @param messageRef the message reference, which may be 1 byte if it is in
+     *     {@link SmsMessage#FORMAT_3GPP} format (see TS.123.040) or 2 bytes if it is in
+     *     {@link SmsMessage#FORMAT_3GPP2} format (see 3GPP2 C.S0015-B).
      *
      * @throws RuntimeException if called before {@link #onReady()} is triggered or if the
      * connection to the framework is not available. If this happens attempting to send the SMS
      * should be aborted.
      */
-    public final void onSendSmsResultSuccess(int token, int messageRef) throws RuntimeException {
+    public final void onSendSmsResultSuccess(int token,
+            @IntRange(from = 0, to = 65535) int messageRef) throws RuntimeException {
         synchronized (mLock) {
             if (mListener == null) {
                 throw new RuntimeException("Feature not ready.");
@@ -266,34 +272,11 @@
      * to the platform.
      *
      * @param token token provided in {@link #sendSms(int, int, String, String, boolean, byte[])}
-     * @param messageRef the message reference. Should be between 0 and 255 per TS.123.040
+     * @param messageRef the message reference, which may be 1 byte if it is in
+     *     {@link SmsMessage#FORMAT_3GPP} format (see TS.123.040) or 2 bytes if it is in
+     *     {@link SmsMessage#FORMAT_3GPP2} format (see 3GPP2 C.S0015-B).
      * @param status result of sending the SMS.
-     * @param reason reason in case status is failure. Valid values are:
-     *  {@link SmsManager#RESULT_ERROR_NONE},
-     *  {@link SmsManager#RESULT_ERROR_GENERIC_FAILURE},
-     *  {@link SmsManager#RESULT_ERROR_RADIO_OFF},
-     *  {@link SmsManager#RESULT_ERROR_NULL_PDU},
-     *  {@link SmsManager#RESULT_ERROR_NO_SERVICE},
-     *  {@link SmsManager#RESULT_ERROR_LIMIT_EXCEEDED},
-     *  {@link SmsManager#RESULT_ERROR_FDN_CHECK_FAILURE},
-     *  {@link SmsManager#RESULT_ERROR_SHORT_CODE_NOT_ALLOWED},
-     *  {@link SmsManager#RESULT_ERROR_SHORT_CODE_NEVER_ALLOWED},
-     *  {@link SmsManager#RESULT_RADIO_NOT_AVAILABLE},
-     *  {@link SmsManager#RESULT_NETWORK_REJECT},
-     *  {@link SmsManager#RESULT_INVALID_ARGUMENTS},
-     *  {@link SmsManager#RESULT_INVALID_STATE},
-     *  {@link SmsManager#RESULT_NO_MEMORY},
-     *  {@link SmsManager#RESULT_INVALID_SMS_FORMAT},
-     *  {@link SmsManager#RESULT_SYSTEM_ERROR},
-     *  {@link SmsManager#RESULT_MODEM_ERROR},
-     *  {@link SmsManager#RESULT_NETWORK_ERROR},
-     *  {@link SmsManager#RESULT_ENCODING_ERROR},
-     *  {@link SmsManager#RESULT_INVALID_SMSC_ADDRESS},
-     *  {@link SmsManager#RESULT_OPERATION_NOT_ALLOWED},
-     *  {@link SmsManager#RESULT_INTERNAL_ERROR},
-     *  {@link SmsManager#RESULT_NO_RESOURCES},
-     *  {@link SmsManager#RESULT_CANCELLED},
-     *  {@link SmsManager#RESULT_REQUEST_NOT_SUPPORTED}
+     * @param reason reason in case status is failure.
      *
      * @throws RuntimeException if called before {@link #onReady()} is triggered or if the
      * connection to the framework is not available. If this happens attempting to send the SMS
@@ -303,8 +286,8 @@
      * send result.
      */
     @Deprecated
-    public final void onSendSmsResult(int token, int messageRef,  @SendStatusResult int status,
-            int reason) throws RuntimeException {
+    public final void onSendSmsResult(int token, @IntRange(from = 0, to = 65535) int messageRef,
+            @SendStatusResult int status, @SmsManager.Result int reason) throws RuntimeException {
         synchronized (mLock) {
             if (mListener == null) {
                 throw new RuntimeException("Feature not ready.");
@@ -324,34 +307,10 @@
      * network.
      *
      * @param token token provided in {@link #sendSms(int, int, String, String, boolean, byte[])}
-     * @param messageRef the message reference. Should be between 0 and 255 per TS.123.040
+     * @param messageRef the message reference, which may be 1 byte if it is in
+     *     {@link SmsMessage#FORMAT_3GPP} format (see TS.123.040) or 2 bytes if it is in
+     *     {@link SmsMessage#FORMAT_3GPP2} format (see 3GPP2 C.S0015-B).
      * @param status result of sending the SMS.
-     * @param reason Valid values are:
-     *  {@link SmsManager#RESULT_ERROR_NONE},
-     *  {@link SmsManager#RESULT_ERROR_GENERIC_FAILURE},
-     *  {@link SmsManager#RESULT_ERROR_RADIO_OFF},
-     *  {@link SmsManager#RESULT_ERROR_NULL_PDU},
-     *  {@link SmsManager#RESULT_ERROR_NO_SERVICE},
-     *  {@link SmsManager#RESULT_ERROR_LIMIT_EXCEEDED},
-     *  {@link SmsManager#RESULT_ERROR_FDN_CHECK_FAILURE},
-     *  {@link SmsManager#RESULT_ERROR_SHORT_CODE_NOT_ALLOWED},
-     *  {@link SmsManager#RESULT_ERROR_SHORT_CODE_NEVER_ALLOWED},
-     *  {@link SmsManager#RESULT_RADIO_NOT_AVAILABLE},
-     *  {@link SmsManager#RESULT_NETWORK_REJECT},
-     *  {@link SmsManager#RESULT_INVALID_ARGUMENTS},
-     *  {@link SmsManager#RESULT_INVALID_STATE},
-     *  {@link SmsManager#RESULT_NO_MEMORY},
-     *  {@link SmsManager#RESULT_INVALID_SMS_FORMAT},
-     *  {@link SmsManager#RESULT_SYSTEM_ERROR},
-     *  {@link SmsManager#RESULT_MODEM_ERROR},
-     *  {@link SmsManager#RESULT_NETWORK_ERROR},
-     *  {@link SmsManager#RESULT_ENCODING_ERROR},
-     *  {@link SmsManager#RESULT_INVALID_SMSC_ADDRESS},
-     *  {@link SmsManager#RESULT_OPERATION_NOT_ALLOWED},
-     *  {@link SmsManager#RESULT_INTERNAL_ERROR},
-     *  {@link SmsManager#RESULT_NO_RESOURCES},
-     *  {@link SmsManager#RESULT_CANCELLED},
-     *  {@link SmsManager#RESULT_REQUEST_NOT_SUPPORTED}
      * @param networkErrorCode the error code reported by the carrier network if sending this SMS
      *  has resulted in an error or {@link #RESULT_NO_NETWORK_ERROR} if no network error was
      *  generated. See 3GPP TS 24.011 Section 7.3.4 for valid error codes and more information.
@@ -360,9 +319,9 @@
      * connection to the framework is not available. If this happens attempting to send the SMS
      * should be aborted.
      */
-    public final void onSendSmsResultError(int token, int messageRef,  @SendStatusResult int status,
-            int reason, int networkErrorCode)
-            throws RuntimeException {
+    public final void onSendSmsResultError(int token,
+            @IntRange(from = 0, to = 65535) int messageRef, @SendStatusResult int status,
+            @SmsManager.Result int reason, int networkErrorCode) throws RuntimeException {
         synchronized (mLock) {
             if (mListener == null) {
                 throw new RuntimeException("Feature not ready.");
@@ -384,9 +343,10 @@
      * the platform is not available, {@link #acknowledgeSmsReport(int, int, int)} will be called
      * with the {@link #STATUS_REPORT_STATUS_ERROR} result code.
      * @param token token provided in {@link #sendSms(int, int, String, String, boolean, byte[])}
-     * @param messageRef the message reference.
-     * @param format the format of the message. Valid values are {@link SmsMessage#FORMAT_3GPP} and
-     *               {@link SmsMessage#FORMAT_3GPP2}.
+     * @param messageRef the message reference, which may be 1 byte if it is in
+     *     {@link SmsMessage#FORMAT_3GPP} format or 2 bytes if it is in
+     *     {@link SmsMessage#FORMAT_3GPP2} format (see 3GPP2 C.S0015-B).
+     * @param format the format of the message.
      * @param pdu PDU representing the content of the status report.
      * @throws RuntimeException if called before {@link #onReady()} is triggered
      *
@@ -394,7 +354,8 @@
      * message reference.
      */
     @Deprecated
-    public final void onSmsStatusReportReceived(int token, int messageRef, String format,
+    public final void onSmsStatusReportReceived(int token,
+            @IntRange(from = 0, to = 65535) int messageRef, @SmsMessage.Format String format,
             byte[] pdu) throws RuntimeException {
         synchronized (mLock) {
             if (mListener == null) {
@@ -419,13 +380,12 @@
      * with the {@link #STATUS_REPORT_STATUS_ERROR} result code.
      * @param token unique token generated by IMS providers that the platform will use to trigger
      *              callbacks for this message.
-     * @param format the format of the message. Valid values are {@link SmsMessage#FORMAT_3GPP} and
-     *               {@link SmsMessage#FORMAT_3GPP2}.
+     * @param format the format of the message.
      * @param pdu PDU representing the content of the status report.
      * @throws RuntimeException if called before {@link #onReady()} is triggered
      */
-    public final void onSmsStatusReportReceived(int token, String format, byte[] pdu)
-            throws RuntimeException {
+    public final void onSmsStatusReportReceived(int token, @SmsMessage.Format String format,
+            byte[] pdu) throws RuntimeException {
         synchronized (mLock) {
             if (mListener == null) {
                 throw new RuntimeException("Feature not ready.");
@@ -450,13 +410,11 @@
     }
 
     /**
-     * Returns the SMS format. Default is {@link SmsMessage#FORMAT_3GPP} unless overridden by IMS
-     * Provider.
+     * Returns the SMS format that the ImsService expects.
      *
-     * @return  the format of the message. Valid values are {@link SmsMessage#FORMAT_3GPP} and
-     * {@link SmsMessage#FORMAT_3GPP2}.
+     * @return  The expected format of the SMS messages.
      */
-    public String getSmsFormat() {
+    public @SmsMessage.Format String getSmsFormat() {
       return SmsMessage.FORMAT_3GPP;
     }