Can we do a direct upgrade from CM 4.1(3) to UCM 6.1(2. If yes, is there any hardware compatibility issues currently all servers are HP hardware platform running Windows 2000, how about Operating system (Windows 2000/2003? or Linux?) how about compatibility with Unity 4.2(1)?, IPCC 4.0(4)are there any issues? Any pros and cons for going 6.x?