We have more than 27 calendar years of hands on experience in eMail, Digital Collaboration, Presence Awareness, extra using HCL Domino, Sametime, Traveler, Connections, and so on. OS platform is not a showstopper for us, let it be AIX, Linux, Windows as long as the application supports it we will. For all in-place upgrade, full fledged upgrade, migration across solutions, we have technical approach with minimal downtime