Whatever it says in your portal is what goes. For older accounts there's a 10x chance (not on rarity, but on chance of summoning if you summon a legendary) on Wythir from Ancients/Sacreds. 

I assume you're referring to new account having a 2x chance of a legendary from Sacreds for what I want to say is the first 24 hours?

I'll believe the boosts when I actually get one. In 8 months and hundreds of shares I've had zilch from any boost