Bank and government mainframe software (including all custom Cobol, Pascal, Fortran code, etc.)
See also:
“Critical infrastructure systems often suffer from “patch lag,” resulting in software remaining unpatched for extended periods, sometimes years or decades. In many cases, patches cannot be applied in a timely manner because systems must operate without interruption, the software remains outdated because its developer went out of business, or interoperability constraints require specific legacy software.”—Superintelligence Strategy by Dan Hendrycks, Eric Schmidt, Alexandr Wang https://www.nationalsecurity.ai/chapter/ai-is-pivotal-for-national-security
See also:
“Critical infrastructure systems often suffer from “patch lag,” resulting in software remaining unpatched for extended periods, sometimes years or decades. In many cases, patches cannot be applied in a timely manner because systems must operate without interruption, the software remains outdated because its developer went out of business, or interoperability constraints require specific legacy software.”—Superintelligence Strategy by Dan Hendrycks, Eric Schmidt, Alexandr Wang https://www.nationalsecurity.ai/chapter/ai-is-pivotal-for-national-security