When Adidas launched the Ultraboost back in 2015, I remember sliding through the crowds of people down on Wall Street to get a look at the brand new shoe. It was the first shoe of its kind to offer so much responsive feedback (you feel an energy return from the ground that keeps you going over many miles) with a knit upper. Over the years, there have been many iterations and colors, often quick to sell out, but Adidas hasn’t made any massive changes to its golden child — until now. Starting this week, Adidas releases the new Ultraboost 19 with a plethora of updates and tweaks.

Since 2015, Adidas has integrated itself into the running community and culture. Head to Adidas Runners.com and you can sign up for the running group in your home city. Once you’re there, you’ll find captains, coaches and more, all designed to help get you out running more. Adidas tapped that international community of runners to get feedback on the original Ultraboost and to test out new versions.

Number 19 is rebuilt from the ground up with 17 individual new parts including an updated Boost foam, a 3D heel frame, and a torsion spring underfoot. The foam supposedly provides 20 percent more BOOST compared to version one and the mix of materials in the Primeknit upper looks remarkably different from past models. The external heel frame is another visual piece that has changed, but the shoes still feel lightweight, weighing in at 10.9 ounces (0.1 ounces lighter than other models). The 10-mm heel drop stays the same and the continental rubber outsole also remains. The new version will only come in a white/black/pink color. Place your order on Saturday, December 15th to get the latest pair. And then, keep an eye on the calendar as more colors will go on sale come February 21, 2019. A little way out, but it’s good to keep track of these things.