Did You Know? Some Airbus A350s Sport Different Winglets

Let's say that you're sitting at an airport gate looking out at all the big jets parked on the apron. Because you're already familiar with the basics of planespotting and aircraft identification, you see that two Airbus A350s are parked side by side. To your knowledge, there is only the A350-900 and the A350-1000, but the jets you see are both -900s. With no updated 'neo' type variants yet to be announced, it seems odd that the two A350s in front of you have different winglets. Why might this be?

https://simpleflying.com/airbus-a350s-has-two-different-winglets/