I had a 3.8.4 installation.
The only language installed is ger-DE.

I ran the update script with:
php update/common/scripts/3.9/updateclasstranslations.php -s admin --language=ger-DE

After updating to 3.9.0 the folder class has damaged name and attribute names.

They appear like this:
a:2:

{s:6:"ger-DE";s:4:"Name";s:16:"always-available";s:6:"ger-DE";}

see also attached screenshot.

Steps to reproduce

1. Install ez publish 3.8.4 in ger-DE only
2. Update to 3.9.0
3. Navigate to class view