diff --git a/CHANGELOG.md b/CHANGELOG.md
index 926d05c8f3..b1d7f00da0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 - Fix UI issue when dealing with an invalid managesieve_default_headers value (#9175)
 - Fix bug where images attached to application/smil messages weren't displayed (#8870)
 - Fix PHP string replacement error in utils/error.php (#9185)
+- Fix regression where `smtp_user` did not allow pre/post strings before/after `%u` placeholder (#9162)
 
 ## Release 1.6.4
 
diff --git a/config/defaults.inc.php b/config/defaults.inc.php
index 85481d22b4..bfa09da1da 100644
--- a/config/defaults.inc.php
+++ b/config/defaults.inc.php
@@ -270,12 +270,12 @@
 // of IMAP host (no prefix or port) and SMTP server e.g. ['imap.example.com' => 'smtp.example.net']
 $config['smtp_host'] = 'localhost:587';
 
-// SMTP username (if required) if you use %u as the username Roundcube
-// will use the current username for login
+// SMTP username (if required)
+// Note: %u variable will be replaced with current user's username
 $config['smtp_user'] = '%u';
 
-// SMTP password (if required) if you use %p as the password Roundcube
-// will use the current user's password for login
+// SMTP password (if required)
+// Note: When set to '%p' current user's password will be used
 $config['smtp_pass'] = '%p';
 
 // SMTP AUTH type (DIGEST-MD5, CRAM-MD5, LOGIN, PLAIN or empty to use
diff --git a/program/lib/Roundcube/rcube_smtp.php b/program/lib/Roundcube/rcube_smtp.php
index ff9c55298a..94d0d70647 100644
--- a/program/lib/Roundcube/rcube_smtp.php
+++ b/program/lib/Roundcube/rcube_smtp.php
@@ -170,18 +170,13 @@ public function connect($host = null, $port = null, $user = null, $pass = null)
             }
         }
 
-        if ($CONFIG['smtp_user'] == '%u') {
-            $smtp_user = (string) $rcube->get_user_name();
-        } else {
-            $smtp_user = $CONFIG['smtp_user'];
-        }
-
         if ($CONFIG['smtp_pass'] == '%p') {
             $smtp_pass = (string) $rcube->get_user_password();
         } else {
             $smtp_pass = $CONFIG['smtp_pass'];
         }
 
+        $smtp_user      = str_replace('%u', (string) $rcube->get_user_name(), $CONFIG['smtp_user']);
         $smtp_auth_type = $CONFIG['smtp_auth_type'] ?: null;
         $smtp_authz     = null;