diff --git a/telephony/java/android/telephony/CarrierConfigManager.java b/telephony/java/android/telephony/CarrierConfigManager.java
index c6cb61d..4d946dc 100644
--- a/telephony/java/android/telephony/CarrierConfigManager.java
+++ b/telephony/java/android/telephony/CarrierConfigManager.java
@@ -668,6 +668,13 @@
             "read_only_apn_types_string_array";
 
     /**
+     * APN fields that user is not allowed to modify
+     * @hide
+     */
+    public static final String KEY_READ_ONLY_APN_FIELDS_STRING_ARRAY =
+            "read_only_apn_fields_string_array";
+
+    /**
      * Boolean indicating if intent for emergency call state changes should be broadcast
      * @hide
      */
@@ -1020,6 +1027,7 @@
         sDefaults.putBoolean(KEY_CSP_ENABLED_BOOL, false);
         sDefaults.putBoolean(KEY_ALLOW_ADDING_APNS_BOOL, true);
         sDefaults.putStringArray(KEY_READ_ONLY_APN_TYPES_STRING_ARRAY, null);
+        sDefaults.putStringArray(KEY_READ_ONLY_APN_FIELDS_STRING_ARRAY, null);
         sDefaults.putBoolean(KEY_BROADCAST_EMERGENCY_CALL_STATE_CHANGES_BOOL, false);
         sDefaults.putBoolean(KEY_ALWAYS_SHOW_EMERGENCY_ALERT_ONOFF_BOOL, false);
         sDefaults.putBoolean(KEY_DISABLE_SEVERE_WHEN_EXTREME_DISABLED_BOOL, true);