diff --git a/src/utils/utf8.php b/src/utils/utf8.php
--- a/src/utils/utf8.php
+++ b/src/utils/utf8.php
@@ -718,20 +718,17 @@
         'mbstring'));
   }
 
-  $result = @mb_convert_encoding($string, $to_encoding, $from_encoding);
-
-  if ($result === false) {
-    $message = error_get_last();
-    if ($message) {
-      $message = idx($message, 'message', pht('Unknown error.'));
+    try {
+      $result = mb_convert_encoding($string, $to_encoding, $from_encoding);
+    } catch (Throwable $ex) {
+      $message = $ex->getMessage();
+      throw new Exception(
+        pht(
+          "String conversion from encoding '%s' to encoding '%s' failed: %s",
+          $from_encoding,
+          $to_encoding,
+          $message));
     }
-    throw new Exception(
-      pht(
-        "String conversion from encoding '%s' to encoding '%s' failed: %s",
-        $from_encoding,
-        $to_encoding,
-        $message));
-  }
 
   return $result;
 }