The majority of 10,000 election jurisdictions nationwide use Windows 7 or an older operating system for voting or tallying — archaic systems vulnerable to hackers, AP reports.

Why it matters: Private vendors, and state finances, determine the security level of election systems, which lack federal requirements or oversight.

What they're saying: J. Alex Halderman, a University of Michigan professor and election security expert, said the country risks repeating "mistakes that we made over the last ... decade-and-a-half when states bought voting machines but didn't keep the software up-to-date."

What's next: Windows 7 reaches its "end of life" Jan. 14, meaning Microsoft stops technical support and patches, although security updates will be provided for a fee through 2023.