Several readers sent word that we're now less than six months away from the end of support for Windows Server 2003. Though the operating system's usage peaked in 2009, it still runs on millions of machines, and many IT departments are just now starting to look at replacements.Although Microsoft publishes support deadlines long in advance -- and has been beating the drum to dump Server 2003 for months -- it's not unusual for customers to hang on too long. Last year, as Windows XP neared its final days of support, there were still huge numbers of systems running the aged OS. Companies lined up to pay Microsoft for extended support contracts and PC sales stabilized in part because enterprises bought new replacement machines. Problems replacing Windows Server 2003 may appear similar at first glance, but they're not: Servers are critical to a business because of the applications that run on them, which may have to be rewritten or replaced.

[In many cases, legacy applications are the sole reason for the continued use of Server 2003.] Those applications may themselves be unsupported at this point, the company that built them may be out of business or the in-house development team may have been disbanded. Any of those scenarios would make it difficult or even impossible to update the applications' code to run on a newer version of Windows Server. Complicating any move is the fact that many of those applications are 32-bit -- and have been kept on Windows Server 2003 for that reason -- and while Windows Server 2012 R2 offers a compatibility mode to run such applications, it's not foolproof.