With just hours left before Microsoft discontinues most support for Windows NT4, many blue-chip companies and e-commerce providers continue to run their web sites on the eight year old operating system, although the last Fortune 100 holdout has migrated.

Microsoft has retired NT4, which was introduced in September 1996, and will cease security updates on Dec. 31, along with pay-per-incident support. Microsoft recently said it will offer only custom support on to users of Windows NT 4.0 Server after Jan. 1. As a result, the number of holdouts running web sites on NT4 has been dwindling. Only 1.4 percent of web-facing hostnames run on Windows NT4/98, according to this month’s Web Server Survey, down from 5.3 percent at the start of 2003.

Retail chain Kroger was the last remaining Fortune 100 company on Windows NT4, but is now serving its site on Windows Server 2003 (IIS6) while using NetBSD for front-end caching or load balancing.

The UK’s FTSE 100 is not as far along, with six member companies still using NT4, following retailer Next PLC’s Christmas Eve upgrade to Windows Server 2003. While Britain’s banks have urged customers to update their computers, several large financial firms (including Lloyds TSB, Legal & General and F&C Asset Management) continue to run their public web sites on Windows NT4. Other FTSE 100 firms continuing to use NT4 include Tomkins, Allied Dome and BB&G.

Another NT4 user is Diebold, the security firm whose systems are widely used in bank cash machines and electronic voting.

Netcraft monitors over 23K hostnames for the top 1.5K Enterprises (Fortune 1K, FT European 500, FT Asia Pacific, FT Japan, FT Eastern Europe) on a monthly basis, providing details of web technology. Contact us for details of the commercial dataset.