Upgrade from SE3 to full version question

I’ve decided to upgrade to The Grand 3 as I love SE3, but have got a bit of a panic on as I am using SE3 a lot in many current projects.

My question is: Does the upgrade install as a separate instrument in addition to SE3 (like how Cubase versions co-exist when you upgrade) or does SE “become” the full version.

Basically, what will happen in my existing projects that use SE3? Will they play without any tinkering?