diff --git a/app/src/main/java/com/eveningoutpost/dexdrip/Home.java b/app/src/main/java/com/eveningoutpost/dexdrip/Home.java
index 85193b0887..ceca112c04 100644
--- a/app/src/main/java/com/eveningoutpost/dexdrip/Home.java
+++ b/app/src/main/java/com/eveningoutpost/dexdrip/Home.java
@@ -6,6 +6,7 @@
 import static com.eveningoutpost.dexdrip.models.JoH.quietratelimit;
 import static com.eveningoutpost.dexdrip.models.JoH.tsl;
 import static com.eveningoutpost.dexdrip.services.Ob1G5CollectionService.getTransmitterID;
+import static com.eveningoutpost.dexdrip.ui.FlipUnits.triggerUnitsChange;
 import static com.eveningoutpost.dexdrip.utilitymodels.ColorCache.X;
 import static com.eveningoutpost.dexdrip.utilitymodels.ColorCache.getCol;
 import static com.eveningoutpost.dexdrip.utilitymodels.Constants.DAY_IN_MS;
@@ -385,6 +386,7 @@ protected void onCreate(Bundle savedInstanceState) {
         setVolumeControlStream(AudioManager.STREAM_MUSIC);
 
         checkedeula = checkEula();
+        triggerUnitsChange(); // Correct defaults that are in mg/dL if we are using mmol/L
 
         binding = ActivityHomeBinding.inflate(getLayoutInflater());
         binding.setVs(homeShelf);
diff --git a/app/src/main/java/com/eveningoutpost/dexdrip/ui/FlipUnits.java b/app/src/main/java/com/eveningoutpost/dexdrip/ui/FlipUnits.java
new file mode 100644
index 0000000000..94e05b76e2
--- /dev/null
+++ b/app/src/main/java/com/eveningoutpost/dexdrip/ui/FlipUnits.java
@@ -0,0 +1,25 @@
+package com.eveningoutpost.dexdrip.ui;
+
+import static com.eveningoutpost.dexdrip.utils.Preferences.handleUnitsChange;
+
+import com.eveningoutpost.dexdrip.Home;
+import com.eveningoutpost.dexdrip.utilitymodels.Pref;
+
+/**
+ * Created by Navid200 on 25/10/2024.
+ *
+ * handleUnitsChange runs only when units are changed.  But, even if we don't change units, we may need to trigger that method.
+ * Triggers handleUnitsChange to correct values that are in mg/dL even though the selected unit is mmol/L.
+ */
+public class FlipUnits {
+
+    public static void triggerUnitsChange() {
+
+        final boolean domgdl = Pref.getString("units", "mgdl").equals("mgdl"); // Identify which unit is chosen
+        if (!domgdl) { // Only if the selected unit is mmol/L
+            handleUnitsChange(null, "mmol", null);
+            Home.staticRefreshBGCharts();
+        }
+    }
+}
+
diff --git a/app/src/main/java/com/eveningoutpost/dexdrip/utils/Preferences.java b/app/src/main/java/com/eveningoutpost/dexdrip/utils/Preferences.java
index e892922fc1..3e9b222c32 100644
--- a/app/src/main/java/com/eveningoutpost/dexdrip/utils/Preferences.java
+++ b/app/src/main/java/com/eveningoutpost/dexdrip/utils/Preferences.java
@@ -1,5 +1,6 @@
 package com.eveningoutpost.dexdrip.utils;
 
+import static com.eveningoutpost.dexdrip.EditAlertActivity.unitsConvert2Disp;
 import static com.eveningoutpost.dexdrip.utils.DexCollectionType.getBestCollectorHardwareName;
 import static com.eveningoutpost.dexdrip.xdrip.gs;
 
@@ -755,6 +756,11 @@ public boolean onPreferenceChange(Preference preference, Object value) {
             String stringValue = value.toString();
             if (isNumeric(stringValue)) {
                 final boolean domgdl = Pref.getString("units", "mgdl").equals("mgdl"); // Identify which unit is chosen
+                double submissionMgdl = domgdl ? Double.parseDouble(stringValue) : Double.parseDouble(stringValue) * Constants.MMOLL_TO_MGDL;
+                if (submissionMgdl > 400 || submissionMgdl < 40) {
+                    JoH.static_toast_long("The value must be between " + unitsConvert2Disp(domgdl, 40) + " and " + unitsConvert2Disp(domgdl, 400));
+                    return false;
+                }
                 preference.setSummary(stringValue + "  " + (domgdl ? "mg/dl" : "mmol/l")); // Set the summary to show the value followed by the chosen unit
                 return true;
             }
@@ -1009,7 +1015,11 @@ private static void bindPreferenceSummaryToValueAndEnsureNumeric(Preference pref
                         .getString(preference.getKey(), ""));
     }
 
-    private static void bindPreferenceSummaryToUnitizedValueAndEnsureNumeric(Preference preference) { // Use this to show the value as well as the corresponding glucose unit as the summary
+    private static void bindPreferenceSummaryToUnitizedValueAndEnsureNumeric(Preference preference) { // Use this to:
+        // 1- show the value as summary;
+        // 2- amend the value in summary with the corresponding glucose unit;
+        // 3- reject inputs outside the 40-400 mg/dL range.
+
         preference.setOnPreferenceChangeListener(sBindNumericUnitizedPreferenceSummaryToValueListener);
         sBindNumericUnitizedPreferenceSummaryToValueListener.onPreferenceChange(preference,
                 PreferenceManager