Sandbox version 2.3.1 and multiple result sets from sp

Hi, I set up a sandbox account yesterday & notice it's on version 2.2.1

I've been using version 2.3.1 locally and have a stored procedure with multiple result sets that works great locally, so perhaps this is a bug in 2.2.1 that was fixed. So my questions are:
1. How to upgrade the sandbox account to 2.3.1 if possible?
2. Am I correct in assuming that multiple result sets from stored procs is fixed in 2.3.1?

Thanks!