Hi Shrikant,
it depends on used version of Genesys Framework and Voice Platform. In case, when you are using the GVP 8.1.7+, you should have the framework 8.1.3+ (especially configuration server). If you meet these prerequisties, you could use the MCP in version 8.5 and rest in version 8.1.x according my information and real-life experience.
On other side, it is strongly recommended to use latest version of Genesys components at least for GVP due to the many hot-fixes and improvements are there. So, is up to you, if you will upgrade just the MCPs or entire GVP/Media Server.
Hope this helps.
Regards,
--Jakub--