diff --git a/lam/HISTORY b/lam/HISTORY
index 03f36be3..d6049f48 100644
--- a/lam/HISTORY
+++ b/lam/HISTORY
@@ -1,4 +1,5 @@
 September 2015 5.1
+  - IMAP: support Windows users
   - SSH public key: check uploaded files if in right format
   - LAM Pro:
    -> MySQL support for cron jobs
diff --git a/lam/lib/modules/imapAccess.inc b/lam/lib/modules/imapAccess.inc
index 02d9f98f..d99368c6 100644
--- a/lam/lib/modules/imapAccess.inc
+++ b/lam/lib/modules/imapAccess.inc
@@ -106,7 +106,7 @@ class imapAccess extends baseModule {
 				"Text" => _("Please enter a comma separated list of domain names (e.g. \"company.com,example.com\"). LAM will only manage mailboxes from these domains.")),
 			'ImapUserNameAttr' => array(
 				"Headline" => _("User name attribute"),
-				"Text" => _("Please choose the attribute to get the IMAP user name. The default is \"mail\" but you can also use \"uid\".")),
+				"Text" => _("Please choose the attribute to get the IMAP user name. The default is \"mail\" but you can also use \"uid\" or \"userPrincipalName\".")),
 			'MailAddress' => array(
 				"Headline" => _("Mailbox"),
 				"Text" => _("This mailbox will be created/deleted.")),