Redirect or message for unsupported browsers?

I am lucky enough to have a number of IE7 users that access my application.

Is there a way I can intercept these users and either redirect them to an older user interface or perhaps put a message on the screen indicating where they should go?

As things currently stand it seems like there is no way to detect these users before the application loads, which for IE7 it obviously would not.

To make matters worse my application is composed using Sencha Architect, so my opportunities to add customisation are somewhat limited. I am thinking the only thing I could do would be to manually add some code to index.html to try and handle this situation.

Has anyone put something in place to handle this?

Thanks, Scott

Redirect or message for unsupported browsers?