Obsolete extensions were detected on the report server computer
Upgrade Advisor detected one or more extensions that are no longer available in the current release.
The report server is configured to use one or more extensions that have been discontinued in this release. Discontinued extensions include:
HTML OWC rendering extension
HTML 3.2 rendering extension
Upgrade can continue, but the discontinued functionality will no longer be available on the upgraded report server.
If you require these extensions, do not upgrade until you find an alternate solution to these requirements. You might need to obtain or build a custom rendering extension that provides the same or similar functionality. For more information about extension deprecation, search for "Discontinued Features (Reporting Services)" in SQL Server Books Online.