diff --git a/Runtime/Code/Model/GuruSDKModel.cs b/Runtime/Code/Model/GuruSDKModel.cs
index d21f20e..be9c302 100644
--- a/Runtime/Code/Model/GuruSDKModel.cs
+++ b/Runtime/Code/Model/GuruSDKModel.cs
@@ -31,7 +31,7 @@ namespace Guru
         public int b_play = 0;
         public int buy_count = 0;
         public bool no_ads = false;
-        public string first_open_time = GetFirstOpenTime();
+        public string first_open_time = "";
         
         public List<PurchasedProduct> purchased;
 
@@ -97,7 +97,15 @@ namespace Guru
             }
         }
 
-        public string FirstOpenTime => first_open_time;
+        public string FirstOpenTime
+        {
+            get => first_open_time;
+            set
+            {
+                first_open_time = value;
+                Save();
+            }
+        }
 
         public bool IsIapUser => PurchasedCount > 0;
         
diff --git a/Runtime/Code/SDK/GuruSDK.Analytics.cs b/Runtime/Code/SDK/GuruSDK.Analytics.cs
index 8af4b45..7fe949f 100644
--- a/Runtime/Code/SDK/GuruSDK.Analytics.cs
+++ b/Runtime/Code/SDK/GuruSDK.Analytics.cs
@@ -395,6 +395,11 @@ namespace Guru
 
         public static void SetFirstOpenTime(string timestamp)
         {
+            if (string.IsNullOrEmpty(timestamp))
+            {
+                timestamp = IPMConfig.FIRST_OPEN_TIME;
+                Model.FirstOpenTime = timestamp;
+            }
             SetUserProperty(Analytics.PropertyFirstOpenTime, timestamp);
         }
         
@@ -431,7 +436,7 @@ namespace Guru
             if (_hasUserPropertiesInitiallyUpdated) return;
             _hasUserPropertiesInitiallyUpdated = true;
             
-            SetFirstOpenTime(Model?.FirstOpenTime ?? GuruSDKModel.GetFirstOpenTime());    //  first_open_time 
+            SetFirstOpenTime(Model?.FirstOpenTime ?? "");    //  first_open_time 
             SetUserIsIAP(Model?.IsIapUser ?? false);    // is_iap_user
             SetUserBLevel(Model?.SuccessLevelId ?? 0);  // b_level
             SetUserBLevel(Model?.TotalPlayedCount ?? 0); // b_play