diff --git a/WebAPI/Controllers/LayersController.cs b/WebAPI/Controllers/LayersController.cs
index 6083e24..6be43da 100644
--- a/WebAPI/Controllers/LayersController.cs
+++ b/WebAPI/Controllers/LayersController.cs
@@ -352,7 +352,7 @@ public class LayersController : Controller
             //"T3-MultiSourceSummary", // AA
             //"T3-MultiSourceYearSummary", // AA/13
             //"T4-SingleSource",
-            //"T1-R1",
+            "T1-R1",
             "T4-R2"
         ];
 
diff --git a/WebAPI/dataProcessors/t1.r1.processor.cs b/WebAPI/dataProcessors/t1.r1.processor.cs
index e54bde4..46e9a62 100644
--- a/WebAPI/dataProcessors/t1.r1.processor.cs
+++ b/WebAPI/dataProcessors/t1.r1.processor.cs
@@ -247,7 +247,7 @@ public class T1R1Processor
         // update time 
         var timeUtc = new List<object>
         {
-            r1!.ModifiedAt.ToString("G")
+            r1!.ModifiedAt.ToString("dd.MM.yyyy HH:mm:ss", CultureInfo.GetCultureInfo("pl-PL"))
         };
         var valueRangeUtcTime = new ValueRange
         {
@@ -261,7 +261,7 @@ public class T1R1Processor
         var warsawTime = TimeZoneInfo.ConvertTimeFromUtc(r1.ModifiedAt.ToUniversalTime(), warsawTimeZone);
         var timeWarsaw = new List<object>
         {
-            warsawTime.ToString("G")
+            warsawTime.ToString("dd.MM.yyyy HH:mm:ss", CultureInfo.GetCultureInfo("pl-PL"))
         };
         var valueRangeWarsawTime = new ValueRange
         {
diff --git a/WebAPI/dataProcessors/t4.r2.processor.cs b/WebAPI/dataProcessors/t4.r2.processor.cs
index cccb149..f6f9283 100644
--- a/WebAPI/dataProcessors/t4.r2.processor.cs
+++ b/WebAPI/dataProcessors/t4.r2.processor.cs
@@ -325,7 +325,7 @@ public class T4R2Processor
         {
             var invoiceDate =
                 DateTime.ParseExact(invoice.Code!.Substring(0, 8), "yyyyMMdd", CultureInfo.InvariantCulture)
-                    .ToString("d");
+                    .ToString("dd.MM.yyyy", CultureInfo.GetCultureInfo("pl-PL"));
             var invoiceRow = new List<object>
             {
                 invoiceDate,