The US government has still not modernized seven of the 11 most critical federal legacy systems as flagged by the Government Accountability Office (GAO) in 2019.

The original report flagged 69 federal legacy systems, of which 11 were identified as the most "critical." According to a report from Fed Scoop, the GAO has said that only three of those systems have been successfully modernized in the six years since.

The remaining legacy systems are between 23 and 59 years old, and some of the hardware in the IT systems is more than two decades old.

According to the GAO, the US federal government currently spends more than $100 billion on IT and cyber-related investments, of which around 80 percent goes on operations and maintenance of existing IT systems.

“Until agencies fully document modernization plans for critical legacy IT systems, their modernization initiatives will have an increased likelihood of cost overruns, schedule delays, and overall project failure,” the GAO wrote. “Project failure would be particularly detrimental not only because of wasted resources, but also because it would prolong the lifespan of increasingly vulnerable and obsolete systems.”

The new report, published July 17, states that "eight of the 11 systems use outdated languages, four have unsupported hardware or software, and seven are operating with known cybersecurity vulnerabilities."

Among those named is the Environmental Protection Agency, which is using "obsolete hardware that is not supported by manufacturers and has known cybersecurity vulnerabilities that cannot be remediated without modernization."

Also using outdated hardware and/or software is the Department of Homeland Security, the Department of the Interior, and the Department of Transportation.

The report notes that the Department of Defense and the Department of Energy currently do not have a modernization plan. The others have plans in place, though in varying states of detail.

Legacy IT in government is a global issue. In January 2025, in the UK, the State of Digital Government review found that, on average, 28 percent of the central government's technology is still considered "legacy." In addition, it noted that while the government spends more than £26 billion ($32.33bn) annually on digital technology, a notable proportion of its technology remains outdated, and service reliability is too low.