I currently have Microsoft SQL Server 2017 (CTP2.1) - 14.0.600.250 (X64) May 10 2017 12:21:23 Copyright (C) 2017 Microsoft Corporation. All rights reserved. Developer Edition (64-bit) on Linux (Ubuntu 16.04.2 LTS).
Are there any earlier versions available? SQL Server 2012, 2014, 2016?
I don't want to run into the problem where I need to back up and restore a database on an earlier version and it giving me an error.