You may get the following exception when upgrading to Team Foundation Server 2013 (TFS 2013) or update packages - when you are using self-signed certificates or your SQL Report server runs unsecured (not using SSL):
TF255455: SQL Server Reporting Services is configured to require a secure connection. However, no HTTPS URL is configured with a valid certificate. Use the Reporting Services Configuration Manager to configure or remove HTTPS support. For more information see http://go.microsoft.com/fwlink/?LinkId=179982
To resolve this issue (without getting valid certificates or securing your site), you can go to your Microsoft SQL Server Reporting Services (SSRS) folder and find the rsreportserver.config file. This is typically in:
C:\Program Files\Microsoft SQL Server\MSRSXX.<ServerInstance>\Reporting Services\ReportServer\rsreportserver.config
Update the "SecureConnectionLevel" from 2 to 0 - and you will be able to run the update. Change it back after the update has completed.