Does 7 day xp elixir stack?

I already have 6 days of double xp left. but if i buy a second one, will i have 3x xp for 7 days?

No it stacks if u get xp elixir from klass or shabot or if u use abiddon(+10% xp)

Combos and regular xP lix stacks with 7 day also :)

I think it stacks with combo elixir and 50% xp elixir. I'm not sure about Abaddon's happy bonus though.