diff --git a/wetb/prepost/GenerateDLCs.py b/wetb/prepost/GenerateDLCs.py
index 7003a8ff65e02d49de7346886947932093316897..4563ccbe28deb9db7f929de67cc4cecdaf270b5b 100644
--- a/wetb/prepost/GenerateDLCs.py
+++ b/wetb/prepost/GenerateDLCs.py
@@ -234,7 +234,7 @@ class GenerateDLCCases(GeneralDLC):
             df = pd.DataFrame(dlc)
             if not os.path.exists(folder):
                 os.makedirs(folder)
-            df.to_excel(os.path.join(folder, sheet.name+'.xls'), index=False)
+            df.to_excel(os.path.join(folder, sheet.name+'.xlsx'), index=False)
 
 
 class RunTest():