"But folks don't worry as much about support for Office as they do for an operating system," said Silver. "There's definitely a risk in running Office 2003 [after patches stop] but you can do a lot of things to reduce the risk significantly, such as turning macros off by default."
The lack of security updates will present special problems to consumers and small business customers running Windows XP and Vista, as the newest editions of the suite, Office 2013 and Office 365, run only on Windows 7 or Windows 8/8.1.
(Large organizations with enterprise and Software Assurance agreements can upgrade from Office 2003 -- if they are still running the 11-year-old suite -- to any newer Office edition.)
Microsoft no longer sells Office 2007 or 2010, the latest versions that run on XP and Vista, either direct or to distributors, but online retailers still have the latter in stock. Newegg, for example, sells Office 2010 for between $100 and $480, depending on the SKU (stock keeping unit) and whether installation media is included.
Miller pointed out that Office 2003 and Windows XP were not the only pieces of Microsoft's portfolio to roll into retirement on April 8.
"It's not just Office 2003, it's not just the front end but it's also the back end. Exchange [Server] 2003 also leaves support that day," Miller said.
As happened to Windows XP and Office 2003, users hung on to Exchange Server 2003, skipping the next edition, Exchange Server 2007. Most enterprises migrated to Windows 7, Office 2010, and Exchange Server 2010 around the same time.
"We're seeing more Exchange holdouts because [the software] was often installed on Windows Server 2003," said Miller, referring to the server-side software that leaves support mid-July 2015. "This could end up being a big thing this year and next, because it's a bigger transition. Some customers are still running Windows Server 2003 on 32-bit hardware, but since that version, it's been all 64-bit. So they may not have the hardware."
For Miller, the migration-from-Server 2003 story will be one to watch carefully.
Coincidentally, Microsoft will also stop serving patches to Office for Mac 2011 Service Pack 2 (SP2) on April 8, and require all users of the OS X edition to run Service Pack 3 to receive and install security updates.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed. His email address is firstname.lastname@example.org.
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