The Rolls-Royce Trent 1000 XE is the current production-standard Trent 1000 high-bypass turbofan for future Boeing 787 deliveries. Rolls-Royce describes its Durability Enhancement package as an evolution from Trent 1000 TEN that increases time on wing and reduces emissions, and says existing TEN customers are being upgraded to the XE standard; the exact two-engine 787 relationship is already represented separately.