I find myself saying this a lot these days, but that's not a typo. In fact, the listed ISO range for the new KONO! Donau film is actually ISO 3-6. With such a low sensitivity, photographers can capture longer exposures in daylight. The film's extremely blue tones serve as a reminder that it's still in the experimental range, but there's an entirely new limit to what you could do with a hand-rolled ISO 3-6 film.
The tones in this film make it easy to perhaps shoot something with a day-for-night feel. But beware: some of the practice shots seem to display what's known as reciprocity failure, which can occur when films don't receive enough (or, more rarely, but also possible: too much) light. Usually marked by areas of what I call "grey red" on film, KONO! Donau seems to exhibit a more "grey green" tone these problem areas. But all one needs to do is simply expose properly (err on the side of "longer") to avoid this phenomenon.
Either way, the film should be a joy to experiment with, this time actually allowing different types of shots as opposed to ones that feel like they merely have the latest Instagram filter over them. But act fast if you are interested: supply is limited at Lomography.com.