What's this airburst mode you're all talking about, was there one in 2.4? I think there was airburst mode in 2.3? Ufopedia still mentions airburst though.
The mode that is now called "impact" was formerly called "airburst", and (apparently) the behaviour is unchanged.
Jumping back to something I'd missed before:
[…]Airbust/Impact fire mode […] will detonate upon reaching target, even if it hasn't hit anything.
It doesn't actually do this. You can confirm by elevating the target point—the grenade
will detonate before reaching the ground (typically, depending on topography), but will consistently overshoot the target point before doing so.
That's kind of sad. I liked having the three-round burst available for engaging small groups. It means there's no way to deal with large groups other than wasting time by firing multiple individuals, or trying to throw hand grenades.
Although the three-round burst
does both deal more total damage and vary the impact point, I don't think the change makes such a huge difference for crowd control—more significant is the reduction in splash radius from 4 for incendiary/HE and 5 for plasma to 3 for all.
~J