This whole lifecycle plan of theirs doesn't obligate them to do anything. Look at Windows XP SP2. Microsoft made two major changes to RPC and DCOM [in SP2] for security reasons, but said they were 'architectural changes.' They weren't required, they said, to make those changes available in Windows 2000, which at that time was still in mainstream support.  -   Michael Cherry     Quotes
This whole lifecycle plan of theirs doesn't obligate them to do anything. Look at Windows XP SP2. Microsoft made two major changes to RPC and DCOM [in SP2] for security reasons, but said they were 'architectural changes.' They weren't required, they said, to make those changes available in Windows 2000, which at that time was still in mainstream support. Michael Cherry