I have done this upgrade a few times without any issues with our clients. Nice new features, plus some fixes. Since you aren't making a huge leap between release levels, you are OK. But, you should always make sure you have a recent backup of the DB, just incase something unexpected happens. You should have the DB backed up before every upgrade.
Also make sure to look over the release notes below just to make sure you other modules are at current levels supported by 10.3.1. If you have NCM, take a close look at the issue described with v6.x.
Orion NCM v6.X is incompatible with Orion NPM v10.3 on Windows Server 2003 running IIS v6
Due to a known application pool sharing issue, Orion Network Configuration Manager (NCM) version 6.X will not function when installed with Orion Network Performance Monitor (NPM) version 10.3 on servers running Windows Server 2003 with Internet Information Services version 6 (IIS6). For more information, see the SolarWinds knowledge base.
I have done several upgrades and the only problem I ever seem to run into is 2012 sql objects. For some reason they seem to stall out the NPM installer on my systems. Pretty sure that there is a GP somewhere that is the culprit but havent found it yet. I usually just uninstall the objects and the installer reinstalls them for me. Other than that pretty smooth.
I did this same upgrade a few months ago. We own NPM, SAM, NTA, IPSLA (VNQM). NCM, and UDT. I upgraded NCM the same night so that they were both the latest version. I had zero issues (other than forgetting my NCM DB password).
This was the smoothest upgrade yet, with the most to do....
