In an interview with Branchés Culture (note: slightly NSFW), Dany talks about his Spirou one-shot with Yann, which he is currently working on. Rather than translate the relevant sections, let’s just summarize:
He talks about the difficulty of escaping from under Franquin’s shadow and come up with a version of the series that is distinctly his own. He had to redo the first five pages because he hadn’t settled on a style yet, but says that readers will just have to deal with it continuing to develop over the course of the album, if for example Fantasio doesn’t look quite the same on page 30 as on page 4.
Other than that, he gets along very well with Yann, sharing the same tastes and points of reference, and spending many hours talking over lunch. He also praises Yann’s ideas, and says that the album will have an ecological theme, but also deal with its abuses: how it can be used as a pretext to manipulate. Not surprisingly, Yann wrote a major role for Seccotine.
The one-shot, or at least the first part of it, is expected for 2017.