Support ran out yesterday, but over 100 Aussie-based sites are still hosted by Microsoft XP.
That's according to Netcraft's April 2014 Web Server Survey, which found Windows XP is still hosting 6,000 websites, globally, including 102 in Australia, which were not named.
Almost one third of this global figure were US-based websites, including 14 government organisations.
The survey also found one well known Aussie website - namely Australia Post's online store (post.com.au) and Postbillpay bill pay service, is running an ever older Window NT4 and IIS 4.0 system.
50,000 websites worldwide are hosted on NT4 servers running Microsoft IIS 4.0.
"One of the busiest sites still running on Windows NT4 is the Australian Postal Corporation's post.com.au, which has been using the same operating system for at least 13 years," according to the Netcraft survey.
The survey also found Microsoft's share of the server market rose by 1.9 per cent, globally, boosted by rising popularity of IIS and Azure.