"I can still watch Standard def on my TV if I have not chosen to upgrade to an HD def TV."
but if you do upgrade to HD (in other words upgrade Dreamweaver) your older SD tv (older extensions) will not work, that is the point.
This is common in software companies as i have pointed out in a previous reply. the version of Office 2010 that i purchase 4 years ago is not supported in Windows 8. If I upgrade to Windows 8, I can also expect that I will need to upgrade to the latest version of Office if I still wish to use Word.