Use or not use that's the question

Hello every body .
i’ve used ionic since last summer and i would like to have an advice from you :
I wnat to dev an app (bussiness) and i would like to know if it’s better to use ionic 2 and learn some new thing like typescript , angular 2 or use ionic 1 ?

I would like to know if ionic 1 should dissapear or if it’s more like angularjs and angular: each version evolve by it’s own way ?

My english is not perfect i’m a french guy so sorry for my bad english !!

thank all and i’ve nice evening