Microsoft has warned enterprise customers that the migration path from XP to Windows 7 won't be any easier than it is to Vista, and the software giant is also offering up recommendations for how companies can move from older versions of Windows to one of its newer client operating systems.

"Moving from XP to Windows 7 is not a magic bullet," said Gavriella Schuster, a senior director of Windows product management, in an interview. "You have the same level of application compatibility from XP to Windows Vista or Windows 7."

Enterprise customers who would have had to replace applications in a move from XP to Vista will still have the same task when they move to Windows 7, she said. However, if customers have already made the leap to Vista, it will be easier to move applications to Windows 7 because it's on essentially the same code base, she said.

In a company blog post attributed to Schuster, Microsoft made recommendations to business customers to help them decide whether they should upgrade to Vista now or wait for Windows 7, which is expected later this year or, at the latest, early next year.

Many companies chose to stick with Windows XP instead of upgrading to Vista, causing Microsoft to keep new PCs with XP pre-installed in the market longer than originally planned. Once Windows 7 is released, which most expect before the end of the year, Microsoft will have two OSes built on essentially the same code base in the market at the same time, and Schuster said customers have asked the vendor how to choose between them.

To no one's surprise, Microsoft recommends that business customers still running XP or older versions of the OS upgrade as soon as possible, citing security and remote-management capabilities in both Vista and Windows 7 that weren't baked into the original XP release.

XP also was released before the majority of PCs in enterprises were laptops, and both Vista and Windows 7 have features that allow IT managers to better manage and secure laptops and mobile devices for the type of mobile workforce found in many enterprises today, Schuster said.

"When you think about Windows XP in that context - it came out in 2001, when less than 10 percent of devices were laptops," she said. "There wasn't ubiquitous broadband. There weren't the levels of compliance and regulatory requirements. There weren't data protections."

What may be surprising in Microsoft's message, however, is that the company doesn't care which of its newer OSes customers move to - Windows Vista or Windows 7 - as long as they do what's best for their individual IT environments.

"What strikes me is that Microsoft is being fairly pragmatic about what the options are for customers," said Al Gillen, an analyst with IDC. "Microsoft seems to recognise the reality that customers aren't going to do what Microsoft tells them to do. They're going to do what's right for them."

Indeed, Schuster said Microsoft is "agnostic" about which OS customers upgrade to. She said Microsoft is just trying to set expectations for any upgrade that may be planned or in progress, so that customers aren't surprised by problems or complexities they may encounter.

Customers should examine their application and hardware environments closely to see which would be the best fit for them. "It really depends on the environment," Schuster said.

She did have some advice for customers depending on what OS they are currently running, and whether or not they have begun migrating to Vista already.

For customers still running Windows 2000, "they clearly need to move fast and need to move to Windows Vista," she said. Extended support for Windows 2000 ends in April 2010, and it will take a company 12 to 18 months to complete the upgrade. "They can't wait for Windows 7," Schuster said.

For companies that are halfway through a migration to Windows Vista Service Pack 1, they should continue that migration as planned, she said. However, if a company has begun piloting Vista and is not yet halfway through the migration process, moving to Vista Service Pack 2 - which should be generally available in April - is a better option.

Some customers have already said they plan to wait for Windows 7, and Microsoft is not recommending they change that course.