For the most part Unity supports Domino for "Windows" version 5.0 through 7.0(x). The supported version will vary depending on the version of Unity you have deployed.
Please refer to the "Cisco Unity 4.x System Requirements, and Supported Hardware and Software, and Support Policies" under the section "Cisco Unity Unified Messaging Configuration". There is a table that oulines the version of Domino supported with Unity. I have attached a link.
http://www.cisco.com/en/US/partner/products/sw/voicesw/ps2237/prod_system_requirements_hardware09186a0080531f2a.html#wp46399
In addition to the requirements above the components of DUC or Domino Unified Communication Services must be installed on multiple servers within the Domino Domain or Cluster. Primariy DUC must be installed on each Domino server that homes Unity Subscribers and each server that contain Address Books that Unity Monitors.
The Unity SRND, located at the link below, outlines all of the requirements for DUC installation.
http://www.cisco.com/application/pdf/en/us/guest/products/ps4608/c1612/ccmigration_09186a008022f487.pdf
The last document you might want to refer to is the Unity Installation Guide for Domino.
http://www.cisco.com/en/US/partner/products/sw/voicesw/ps2237/products_installation_guide_book09186a008041fcfb.html
Let me know if this helps
