diff --git a/app/src/main/cpp/MicroPhoto.cpp b/app/src/main/cpp/MicroPhoto.cpp
index 97dbe010..7c717ca7 100644
--- a/app/src/main/cpp/MicroPhoto.cpp
+++ b/app/src/main/cpp/MicroPhoto.cpp
@@ -1421,3 +1421,15 @@ Java_com_xypower_mpapp_MicroPhotoService_releasePowerControl(
 
     return JNI_TRUE;
 }
+
+extern "C"
+JNIEXPORT jint JNICALL
+Java_com_xypower_mpapp_MainActivity_getCustomAppId(JNIEnv *env, jobject thiz) {
+#ifdef USING_N938
+    return 2;
+#elif defined(USING_PLZ)
+    return 1;
+#else
+    return 0;
+#endif
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/xypower/mpapp/MainActivity.java b/app/src/main/java/com/xypower/mpapp/MainActivity.java
index 5fa35cc0..47b94a97 100644
--- a/app/src/main/java/com/xypower/mpapp/MainActivity.java
+++ b/app/src/main/java/com/xypower/mpapp/MainActivity.java
@@ -72,7 +72,18 @@ public class MainActivity extends AppCompatActivity {
 
         Date date = new Date(BuildConfig.BUILD_TIMESTAMP);
         SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");
-        String caption = actionBar.getTitle().toString() + " v" + MicroPhotoContext.getVersionName(getApplicationContext()) + "  " + sdf.format(date);
+        String caption = "MP";
+        switch (getCustomAppId()) {
+            case 1:
+                caption = "RP";
+                break;
+            case 2:
+                caption = "N938";
+                break;
+            default:
+                break;
+        }
+        caption += " v" + MicroPhotoContext.getVersionName(getApplicationContext()) + "  " + sdf.format(date);
         sdf = new SimpleDateFormat("MM-dd HH:mm");
         caption += " / " + sdf.format(new Date());
         actionBar.setTitle(caption);
@@ -629,4 +640,6 @@ public class MainActivity extends AppCompatActivity {
     }
 
 
+    private native int getCustomAppId();
+
 }
\ No newline at end of file