Ubuntu 13.10 has been released recently. This new Ubuntu versions uses apache 2.4 by default which causes various problems. The apache configuration Syntax has been changed from apache 2.2 to 2.4, so websites that were created for apache 2.2 will fail on the new version. ISPConfig 3.0.5.3 is not compatible with apache 2.4 yet, so we highly recommend to not update to Ubuntu 13.10 until we release a ISPConfig update with Apache 2.4 support.
