@Ander It does have a more complicated schedule that's aware of differences in people, and yes, you can choose the "classic f.lux" preset to have the software operate like the previous version.
As we said in the update notes, we think there's a good chance that the previous version was not doing a good job reducing light levels enough to avoid significant sleep disruption. So rather than ask you to dim all your lights at 5PM in the winter, this version tries to split the difference...a more moderate setting at sundown, and a more intense change before bed.
Our goal with the software is to begin to fix a major problem we think is happening with all electric lighting and screens, and so we want it to serve the role of educating people about these problems and how they might think about them.
So we think we have made the easy things easy - a big slider you can move to look the way you like, and some presets. And after that if you're happy you don't need to read any more.
But there is very deliberately some confusing text that explains how your screen is programming your circadian clock, and this is not easy, but we think it is important, and that's why we did it, anyway.