There is way to forward Windows 2012 R2 vCenter Server 6.0 to remote syslog server ?
I read It's possible only with Appliance, right?
Officially it's VCSA only, but this may help: https://www.virtuallyghetto.com/2012/08/forwarding-vcenter-server-logs-to.html
So for having supported solution It's necessary to replace my Windows vCenter to Virtual Server Appliance ?
I have both ESXi 6.0 and vCenter 6.0 (+ SQL Standard Edition) , can I upgrade only Windows vCenter srv to 6.5/6.7 VCSA keeping ESXi older version ?
Generally yes, especially in the long run
Vsphere 6.0 is not longer supported
VCSA 6.7 is the last version that is able to talk to ESXi 6.0
It's advised actually to update ESXi version as well - at least to 6.5
As above you can run VCSA 6.7 with 6.0 hosts, but if you are running anything like production workloads you should get those hosts onto at least 6.5 so you are on a supported and updated version.