The bulletin was issued to tax agents earlier this week via the ATO's electronic lodgement system in the form of a confirmation notice tax practitioners received after lodging tax assessments.
The bulletin warned tax agents that the ATO was "likely to reduce support" for the first edition of Windows 98 from December 2004. Support for Windows 98 Second Edition and Windows Millennium Edition would continue "until further notice".
Accordingly, the ATO advised practitioners still reliant on the original release of the operating system to upgrade their software by the end of the year.
However, CPA Australia spokesperson, Garry Addison, today said he had been advised by the ATO officers that the information was released by mistake.
"It must have slipped through the net," said Addison.
Addison said agents using Windows 98 first edition would still be able lodge returns but would be able to call on the ATO for help if they encountered technical difficulties.
Operating system upgrades can impose a heavy burden on small and independent tax agents for whom the task may involve additional hardware and software upgrades to side-step software compatibility issues.
According to Addison, the ATO would work through the decision with industry groups and the electronic advisory committee for tax practitioners.
"We have some concerns but if we can progress through the working group then we may able to address the issues involved," he said.
Microsoft has pledged to continue providing support for Windows 98 until the end of 2006.