This bill reforms the Technology Modernization Fund, a federal program that finances IT modernization projects across government agencies. The legislation refocuses the fund's mission on retiring outdated legacy systems, improving cybersecurity, and enhancing agency efficiency, while establishing stronger oversight and repayment requirements to ensure agencies return funds to keep the program operational. The bill requires agencies to inventory their high-risk legacy IT systems and report them to the Federal Chief Information Officer by September 30, 2024, with the government identifying the ten riskiest systems within 90 days and reporting these findings to Congress. It also tightens funding controls by requiring incremental transfers tied to development milestones, adding fraud detection measures, and expanding the Technology Modernization Fund Board to include a Cybersecurity and Infrastructure Security Agency representative. The fund's sunset date moves to December 31, 2031, giving agencies a clear timeline for modernization efforts and establishing accountability mechanisms to prevent misuse of taxpayer funds.