Hi Nagarajan,
Sorry to say that there is no Licensing support for any Unity 3.x version :(
Cisco Announces End of Support for Cisco Unity 3.0
Effective January 10, 2005 Cisco will discontinue support for Cisco Unity 3.0 systems.
End of Support Details
End of Support announcement: January 8, 2003
Affected product: Cisco Unity 3.0
End of Sale date for Cisco Unity 3.0: January 10, 2003
End of Support date: January 10, 2005.
http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_eol_notice09186a008032d4d6.html
Cisco Announces End of Support for Cisco Unity 3.1
End of Support Details
End of Support announcement: May 1, 2003
Affected product: Cisco Unity 3.1
End-of-Sale and End-of-Life Announcement for Cisco Unity 3.1
End of Sale date for Cisco Unity 3.1: October 31, 2003
End of Support date: October 31, 2006
http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_eol_notice09186a008032d506.html
Hope this helps! I know its not the answer that you wanted to hear,
Rob