Separate DLL for SharePoint 2013 and SharePoint 2016 on Server side coding C# .Net

Hi,

I had created a web service developed in Visual Studio 2015 using SharePoint 2016 DLL . It is working fine if I publish that code on SharePoint 2016 server. But when I am hosting same application on SharePoint 2013 it is not able to pick spfarm.local.

I only have SharePoint 2016 server but my client have both SP2016 and SP2013 servers. Is there any way I can publish my code in SP2016 and make it run on SP2013.