don't wait for an answer, go with Prestashop 1.6 its stable!
Prestashop 1.7 is still buggy, check the forum, the french developers call Alpha Products "Stable"
And they don't have an ear or eye for the community, I asked so many times to remove ID's from url's what happened? NOTHING!
Those ugly ID's are still there and Prestashop has the worst urls for the products and categories with those ID's!