Cortana not working with band.

Doesn't downloading the preview from the Microsoft Health App void any warranty you have on your phone?

Yes. That's the message I receive when I start to update to the preview....
 
I was told I needed Denim to have the Cortana tile on my Band. MS Band support told me that. I have Windows Phone 8.1 (8.10.12397.895) but only Lumia Cyan.

Denim is coming in September of 2014, or Late 2014, or by the end of the year, or early 2015, or by end of January 2015, or end of February 2015, or, my favorite answer yet from some MS twitt: 'SOON'