diff --git a/core/api/current.txt b/core/api/current.txt
index 04207145673fa..60fa2ffd1693e 100644
--- a/core/api/current.txt
+++ b/core/api/current.txt
@@ -43102,18 +43102,11 @@ package android.telephony.data {
   public final class TrafficDescriptor implements android.os.Parcelable {
     method public int describeContents();
     method @Nullable public String getDataNetworkName();
-    method @Nullable public String getOsAppId();
+    method @Nullable public byte[] getOsAppId();
     method public void writeToParcel(@NonNull android.os.Parcel, int);
     field @NonNull public static final android.os.Parcelable.Creator<android.telephony.data.TrafficDescriptor> CREATOR;
   }
 
-  public static final class TrafficDescriptor.Builder {
-    ctor public TrafficDescriptor.Builder();
-    method @NonNull public android.telephony.data.TrafficDescriptor build();
-    method @NonNull public android.telephony.data.TrafficDescriptor.Builder setDataNetworkName(@NonNull String);
-    method @NonNull public android.telephony.data.TrafficDescriptor.Builder setOsAppId(@NonNull String);
-  }
-
   public final class UrspRule implements android.os.Parcelable {
     method public int describeContents();
     method @IntRange(from=0x0, to=0xff) public int getPrecedence();
diff --git a/telephony/java/android/telephony/data/TrafficDescriptor.java b/telephony/java/android/telephony/data/TrafficDescriptor.java
index d813bc58fe6f4..f400a5e39704b 100644
--- a/telephony/java/android/telephony/data/TrafficDescriptor.java
+++ b/telephony/java/android/telephony/data/TrafficDescriptor.java
@@ -21,6 +21,7 @@ import android.annotation.Nullable;
 import android.os.Parcel;
 import android.os.Parcelable;
 
+import java.util.Arrays;
 import java.util.Objects;
 
 /**
@@ -31,11 +32,11 @@ import java.util.Objects;
  */
 public final class TrafficDescriptor implements Parcelable {
     private final String mDnn;
-    private final String mOsAppId;
+    private final byte[] mOsAppId;
 
     private TrafficDescriptor(@NonNull Parcel in) {
         mDnn = in.readString();
-        mOsAppId = in.readString();
+        mOsAppId = in.createByteArray();
     }
 
     /**
@@ -45,14 +46,15 @@ public final class TrafficDescriptor implements Parcelable {
      *
      * @hide
      */
-    public TrafficDescriptor(String dnn, String osAppId) {
+    public TrafficDescriptor(String dnn, byte[] osAppId) {
         mDnn = dnn;
         mOsAppId = osAppId;
     }
 
     /**
      * DNN stands for Data Network Name and represents an APN as defined in 3GPP TS 23.003.
-     * @return the DNN of this traffic descriptor.
+     * @return the DNN of this traffic descriptor if one is included by the network, null
+     * otherwise.
      */
     public @Nullable String getDataNetworkName() {
         return mDnn;
@@ -60,10 +62,11 @@ public final class TrafficDescriptor implements Parcelable {
 
     /**
      * OsAppId is the app id as defined in 3GPP TS 24.526 Section 5.2, and it identifies a traffic
-     * category.
-     * @return the OS App ID of this traffic descriptor.
+     * category. It includes the OS Id component of the field as defined in the specs.
+     * @return the OS App ID of this traffic descriptor if one is included by the network, null
+     * otherwise.
      */
-    public @Nullable String getOsAppId() {
+    public @Nullable byte[] getOsAppId() {
         return mOsAppId;
     }
 
@@ -80,7 +83,7 @@ public final class TrafficDescriptor implements Parcelable {
     @Override
     public void writeToParcel(@NonNull Parcel dest, int flags) {
         dest.writeString(mDnn);
-        dest.writeString(mOsAppId);
+        dest.writeByteArray(mOsAppId);
     }
 
     public static final @NonNull Parcelable.Creator<TrafficDescriptor> CREATOR =
@@ -101,7 +104,7 @@ public final class TrafficDescriptor implements Parcelable {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
         TrafficDescriptor that = (TrafficDescriptor) o;
-        return Objects.equals(mDnn, that.mDnn) && Objects.equals(mOsAppId, that.mOsAppId);
+        return Objects.equals(mDnn, that.mDnn) && Arrays.equals(mOsAppId, that.mOsAppId);
     }
 
     @Override
@@ -121,10 +124,12 @@ public final class TrafficDescriptor implements Parcelable {
      *     .setDnn("")
      *     .build();
      * </code></pre>
+     *
+     * @hide
      */
     public static final class Builder {
         private String mDnn = null;
-        private String mOsAppId = null;
+        private byte[] mOsAppId = null;
 
         /**
          * Default constructor for Builder.
@@ -144,12 +149,12 @@ public final class TrafficDescriptor implements Parcelable {
         }
 
         /**
-         * Set the OS App ID.
+         * Set the OS App ID (including OS Id as defind in the specs).
          *
          * @return The same instance of the builder.
          */
         @NonNull
-        public Builder setOsAppId(@NonNull String osAppId) {
+        public Builder setOsAppId(@NonNull byte[] osAppId) {
             this.mOsAppId = osAppId;
             return this;
         }
diff --git a/telephony/java/android/telephony/data/UrspRule.java b/telephony/java/android/telephony/data/UrspRule.java
index e2c47fd86b4bf..fbe199975b00b 100644
--- a/telephony/java/android/telephony/data/UrspRule.java
+++ b/telephony/java/android/telephony/data/UrspRule.java
@@ -84,8 +84,8 @@ public final class UrspRule implements Parcelable {
             android.hardware.radio.V1_6.TrafficDescriptor td) {
         String dnn = td.dnn.getDiscriminator() == OptionalDnn.hidl_discriminator.noinit
                 ? null : td.dnn.value();
-        String osAppId = td.osAppId.getDiscriminator() == OptionalOsAppId.hidl_discriminator.noinit
-                ? null : new String(arrayListToPrimitiveArray(td.osAppId.value().osAppId));
+        byte[] osAppId = td.osAppId.getDiscriminator() == OptionalOsAppId.hidl_discriminator.noinit
+                ? null : arrayListToPrimitiveArray(td.osAppId.value().osAppId);
         TrafficDescriptor.Builder builder = new TrafficDescriptor.Builder();
         if (dnn != null) {
             builder.setDataNetworkName(dnn);