diff --git a/src/utils/utf8.php b/src/utils/utf8.php
--- a/src/utils/utf8.php
+++ b/src/utils/utf8.php
@@ -718,7 +718,20 @@
         'mbstring'));
   }
 
-  $result = @mb_convert_encoding($string, $to_encoding, $from_encoding);
+  $available_encodings = mb_list_encodings();
+  foreach ($available_encodings as $enc) {
+    $available_encodings =
+      array_merge($available_encodings, mb_encoding_aliases($enc));
+  }
+  $available_encodings =
+    array_change_key_case(array_fill_keys($available_encodings, true));
+  $to_encoding_is_valid =
+    array_key_exists(strtolower($to_encoding), $available_encodings);
+  if ($to_encoding_is_valid) {
+    $result = @mb_convert_encoding($string, $to_encoding, $from_encoding);
+  } else {
+    $result = false;
+  }
 
   if ($result === false) {
     $message = error_get_last();