If you bought Corel’s WinDVD, update now, or you won’t be allowed to play future high-definition movies you purchase. The encryption keys packed in with WinDVD were discovered by the public, and were thus blacklisted. This is not a mincing of words. As Corel puts it:
Please be aware that failure to apply the update will result in AACS-protected HD DVD and BD playback being disabled.
Expect many such update necessities in the future, as the encryption keys of more and more software products are discovered. As you are no doubt aware, the playing of purchased high-def movies is strictly illegal on computers that aren’t running the latest versions of Windows, and on any hardware that hasn’t been pre-approved.
These key revocations are necessary in order to stop the unauthorized playing of legally purchased high-def movies, as well as to stop the flow of pirated movies. As you are fully aware, this kind of encryption is so effective that it has yet to stop a single high-def film from appearing on filesharing networks.