Cloud Build Version vs Locally Installed Unity Version? (bugfixes and etc.)

I've been developing a 2D game with Unity 5.1, and running into a handful of mobile performance issues. I notice that a few of the newer build releases of unity (5.2.x) have some bugfixes and performance improvements.

I use Unity Cloud Build, so my question is: do I need to upgrade my locally installed Unity as well, to get these bugfixes/performance improvements, or since I'm using Cloud Build, does it just build with the latest version of 5.x regardless of the local version I have installed?

In other words, if I want to see improvements introduced in a newer version of Unity, does building via Cloud Build incorporate those fixes as well?