The Australian Department of Home Affairs has extended its mainframe contract with IBM for at least another four years.

The AU$235 million (US$182.7 million) deal extends the Department’s current agreement with IBM to July 2025.

IT News, which first reported the extension, reports that Home Affairs uses its mainframe to host a number of the country’s mission-critical traveller, cargo and trade systems.

Home Affairs first signed the contract with IBM in June 2007. It had previously been extended in 2015, 2017, and 2018, and this latest extension brings the total value of the contract to AU$924.2 million ($718.6 million) over 18 years.

Last year the Department put out a tender requesting information and advice around ‘modernising and optimising existing mainframe workloads, which may or may not lead to a Mainframe Modernisation and Optimisation Project.’

A spokesperson told IT News that the department’s “complex and large” environment meant that “any move away from mainframe platforms will take many years.”

Earlier this month Home Affairs signed a new five-year hosting deal with Canberra Data Centres to migrate out of Global Switch’s Sydney facility. The move comes as part of an exodus of Australian Government departments from Global Switch facilities in the wake of its takeover by Chinese steel giant Shagang.