diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index b60a889..538006c 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -143,7 +143,7 @@ variables:
       # calcolo versione formato numerico
       $versionTxt = $env:MACH_VERS
       echo $versionTxt
-      $versionMonthTxt = $env:MACH_VERS.Substring(3,1)
+      $versionMonthTxt = $versionTxt.Substring(3,1)
       # calcolo mese formato numerico
       $versionMonthNum = 999
       if ( $versionMonthTxt -eq "a") {