The meeting has been organised by the Corporate IT Forum, Tif, in response to users' concerns, particularly about security, once mainstream support has officially ended.
Released in 1996, NT 4.0 was widely regarded as the first fully functional Microsoft server operating system. Although it wassuperseded by Windows 2000 and then Windows 2003 in April last year, many users are still running NT 4.0.
Microsoft will officially end support for the NT 4.0 operating system in December. It is urging users to upgrade to newer versions of its operating system, but some businesses are reluctant to change systems that are working well.
Security is the primary concern of Tif members, said David Roberts, chief executive of Tif. He added, "Many organisations will continue to run large-scale enterprise applications on NT 4.0 for some time. Some businesses have up to 100 internal servers running NT4.0.
"We cannot stop the business just because Microsoft stops support. The workshop will look at patching to protect against new types of security threat."
Microsoft recommends several third-party companies that can migrate NT 4.0 users to Windows 2003.
For those that do not want to migrate, a Microsoft spokeswoman encouraged them to contact one of Microsoft's gold certified support partners, as it said many would be providing support for the product. She said online self-help would remain available for users and suggested that anyone who required support (including hotfix support) should contact Microsoft to discuss potential custom support options.
Roberts suggested Microsoft hand over the NT 4.0 source code - either to a software escrow agency, or to the user community. This would allow users and third-party software houses to also support the product. Microsoft said it had no plans to do this.