Check it out here

http://www.pro-tools-expert.com/home-page/2017/10/14/sonarworks-release-reference-4-zero-latency-speaker-headphone-calibration-perfect-for-tracking
 
Buy here

https://www.sonarworks.co.reference/upgrade-policy

Great news for playing guitar through it on headphones.
Not really sure I understand the upgrade tables though. I have the headphone version of 3... Is the upgrade free or $19??

Depends when you registered/bought it.  If you bought it before Sept 10, 2017, it's $19 (only for a limited time).  If you bought it after Sept 10, 2017 the upgrade is free.  Doesn't look like you can buy it just yet, I entered my serial number and was taken to a page that said it wouldn't be available to actually order till Oct 17.
 
https://storeus.sonarworks.com/products/upgrade-reference-3-to-reference-4
 

Lol, looking again not sure how I missed that. Thanks

FYI, when you bought Ref 3 Systemwide you got a trial license for Speaker calibration so you can use Systemwide with your monitors. Speaker calibration would expiration but the resulting calibration curve/data was usable forever with Ref 3 Systemwide. With the Ref 4 Headphone upgrade you no longer have access to the Ref 3 speaker calibration data. You must purchase the Studio Edition upgrade to get it. 

Here’s the upgrade chart again.

https://www.sonarworks.co...olicy#purchased-during

If you follow all the upgrade buttons from the page @lawajava listed, you can enter your activation codes and it will tell you what your upgrade path and cost is.

Anyone know how to salvage your authorization code? I seem to have lost the email. I really hate the companies that don't have a user area. I fired off an email but nothing yet