Users of older versions of Windows or Mac are reaching the limits of the capabilities of their current operating systems.

Four years since Mac OS X and Windows XP shipped, the need to upgrade to new systems is growing for millions, the Washington Post implies.

IDC reports that of 514 million PCs running Windows almost 21 per cent use veteran operating systems Windows 95, 98 and Millennium Edition releases. And "just about half" of 19 million Macs running Mac OS use pre-OS X releases.

All such users aren't enjoying the modern features, applications and device recognition abilities of new systems, observes the Washington Post.

The report recognises that these veteran systems may happily perform the functions their users require, but observes: "Home computing these days has little in common with five years ago, and not all of these changes leave room for older systems."

The list of missing features creates a digital divide: Windows 95 users, for example, enjoy no USB support; Windows 98 offers little in the way of multimedia facilities; and Microsoft Office 2003 does not run on Windows 98 SE and ME. Windows 2000 carries "little or no built-in support" for wireless standards.

Mac users with older systems face similar limitations: Mac OS 8-8.5 don't support modern browsers or USB; Mac OS 8.6-9.2 don't run any modern browsers, either.

"If you're spending any time with digital photos, music or video and you're not running at least Win 2000 or Jaguar, forget it," advises the report.

"The alternative is endless fussing with your computer, the kind of drudgery that will make you feel old," the report concludes.