I have got a NetWare 6 environment for which the details are given below.

Two servers with:
NetWare 6
SP 5
eDirectory 8.7.3 SMP
NDS 10550.98

Authentication server is holding master replica and secondary server holding Read/Write replica.

Authentication server is also running GroupWise 6 PO, DOM and GWIA.

Can I install third server in the existing tree as OES NetWare 6.5 which will act as file server, keeping the existing master replica as it is?

What is the best way to have third server with OES NetWare 6.5 in the existing tree? Which changes (for example upgrading eDirectory on all server etc.) will be compalsory to have this third OES NetWare 6.5 server in the network?

What precautions I should take before I deploy this new server?

I will appreciate if someone can share the checklist and/or plan for this activity.