Just started to Get this error code 0004

I just started to get this error code, the only thing that changed was the Roasttime update. I checked the IR glass (I dont have the new IBTS) and cleaned it but still the same issue. Any help would be great thanks!

Your Bullet is overheating. Check your IR glass is clean…Really clean!
Alternatively you can buy the IBTS upgrade kit.

That happened to me after updating to firmware Beta 602.
All back to normal downgrading to Stable 591