Fatal: strlen() expects parameter 1 to be string MoGenerator.php

[Alexkurd]

Uncaught TypeError: strlen() expects parameter 1 to be string, int given in \lib\vendors\gettext\gettext\src\Generator\MoGenerator.php:70
Stack trace:
#0 \lib\vendors\gettext\gettext\src\Generator\MoGenerator.php(70): strlen(123456)
#1 \lib\vendors\gettext\gettext\src\Generator\Generator.php(12): Gettext\Generator\MoGenerator->generateString(Object(Gettext\Translations))

test.po file

msgid ""
msgstr ""
"Content-Transfer-Encoding: 8bit\n"

msgid "123456"
msgstr "12345"

$filename = "test.po";
$poLoader = new Gettext\Loader\PoLoader();
$data = $poLoader->loadFile($filename);

$moGenerator = new Gettext\Generator\MoGenerator();
$filename = str_ireplace('.po', '.mo', $filename);
$moGenerator->generateFile($data, $filename);

[oscarotero]

I just released a the new version 5.5.4 including a fix for this bug.
Thanks!