diff -urN ../roundcubemail-1.6.1.orig/plugins/managesieve/lib/Roundcube/rcube_sieve_engine.php ./plugins/managesieve/lib/Roundcube/rcube_sieve_engine.php
--- ../roundcubemail-1.6.1.orig/plugins/managesieve/lib/Roundcube/rcube_sieve_engine.php	2023-01-23 22:03:13.000000000 +0200
+++ ./plugins/managesieve/lib/Roundcube/rcube_sieve_engine.php	2023-04-15 15:44:39.988618000 +0300
@@ -3244,6 +3244,7 @@
         // find common headers used in script, will be added to the list
         // of available (predefined) headers (#1489271)
         foreach ($this->script as $rule) {
+          if (isset($rule['tests'])) {
             foreach ((array) $rule['tests'] as $test) {
                 if ($test['test'] == 'header') {
                     foreach ((array) $test['arg1'] as $header) {
@@ -3260,6 +3261,7 @@
                     }
                 }
             }
+          }
         }
 
         ksort($headers);
diff -urN ../roundcubemail-1.6.1.orig/plugins/managesieve/lib/Roundcube/rcube_sieve_vacation.php ./plugins/managesieve/lib/Roundcube/rcube_sieve_vacation.php
--- ../roundcubemail-1.6.1.orig/plugins/managesieve/lib/Roundcube/rcube_sieve_vacation.php	2023-01-23 22:03:13.000000000 +0200
+++ ./plugins/managesieve/lib/Roundcube/rcube_sieve_vacation.php	2023-04-15 15:37:29.006313000 +0300
@@ -160,7 +160,7 @@
                 ]);
             }
             else if ($active) {
-                $list[$idx] = $rule['name'] ?: ('#' . ($idx + 1));
+                $list[$idx] = !empty($rule['name']) ? $rule['name'] : ('#' . ($idx + 1));
             }
         }