Hello everybody. we are currently running 10.3.1, Our SQL server is currently at 2008. We are planning on upgrading our server in the coming month to Operating System MS Server 2012 R2 and SQL version to SQL Server 2016.
is 10.3.1 compatible with these items
It looks SQL Server 2014 is the newest version that is supported with 10.3.1. Microsoft SQL Server database requirements for ArcGIS 10.3.x—Help | ArcGIS Desktop
You would need to move to 10.4.x or newer client to use SQL Server 2016: Microsoft SQL Server database requirements for ArcGIS 10.4.x—System Requirements | ArcGIS Desktop
With ArcMap 10.3,Microsoft SQL Server 2014 is the highest version that is supported.
Microsoft SQL server 2016 is supported with ArcMap 10.4 and 10.5.
Here are link for reference: