Hi Edwin,
Yes, versions are the same. I am just thinking - maybe I have installed wrong client software, I took it from here:
http://standardinstall.com/main?appos=4&appcc=POL&appprod=StandardERP&vermode=0
Server I installed is "Standard ERP Server 2016-12-18" and client I try to connect with is "Standard ERP 2016-12-18".
Kindest regards,
Pawel