[till]

@HermannS: Maybe you can give me a hint of what might have caused this problem on your server. Have you disabled any php functions in php.ini or did you do any other changes which might cause php to fail to write files? I tested the update many times and I'am not able to get it to fail in a way that 0Byte files get written by PHP.

Which tutorial did you use to install your server and have you modified any config files after the initial setup?