SQL Server 2005 SP2 Brings Self-upgrading Catalogs
A little known but very useful SSRS feature which debuted in SQL Server 2005 SP2 is that the SSRS Windows service automatically upgrades the report catalog (ReportServer database) if required. As I discussed in this blog, you may need to swap the report catalog for testing or troubleshooting purposes. In the past, you had to manually upgrade the catalog from a previous version using the Report Services Configuration Utility or using the rskeymgmt utility.
Starting with SQL Server 2005 SP2, when the SSRS Windows Service connects to the report catalog it runs the stored procedure to get the database version of the catalog. If the versions don’t match, SSRS Windows Service calls down to WMI to generate an upgrade script and applies it. The service executes the catalog version check every time it connects to the catalog.