I performed this upgrade over the weekend and am still working with TAC on some issues. I'm told that they haven't seen many of these upgrades yet. Take a look at the Release Notes before you upgrade:
http://www.cisco.com/univercd/cc/td/doc/product/voice/sw_ap_to/apps_4_0/english/relnotes/crs401rn.pdf
Pay particular attention to the Important Notes section and look at bugs CSCsb20774 and CSCsb69904. Also, if your installation is integrated with Active Directory, be aware that your CallManagers need to be able to write to AD. You can enable that by performing the following steps:
Step 1 Browse to C:\dcdsrvr\config, and open the file,
UMDirectoryConfiguration.ini, in Notepad.
------------------------------------------------------------------------
--------
Caution You must open the file in Notepad. Opening the file in another text
editor application may corrupt the file.
------------------------------------------------------------------------
--------
Step 2 In the UMDirectoryConfiguration.ini file, locate the key,
UserDirAccess.
Step 3 Change the UserDirectAccess value to true.
Step 4 In Notepad, choose File > Save to save the file.
Step 5 Close the UMDirectoryConfiguration.ini file.
Step 6 Choose Start > Run.
Step 7 Enter regedit in the Open field and click OK.
Step 8 Browse to \\HKEY_LOCAL_MACHINE\Software\Cisco Systems, Inc.\Directory
Configuration within the registry.
Step 9 In the right pane, double-click the DirAccess registry key.
Step 10 Delete the false registry entry and enter true as the new registry
entry.
Step 11 Restart the IIS Admin Service and its dependent services by choosing
Start > Programs > Administrative Tools> Services.
Step 12 Right-click IIS Admin Service and then choose Restart.
Step 13 A dialog box prompts you to restart dependent services. These
services may differ depending on your configuration. Click Yes.
Step 14 Restart the dependent services.
Hope this helps.
Brandon
