Microsoft has tamped down the earth on XP's grave, steered Internet Explorer toward the nursing home, and is trying to convince everyone Windows 10 is a bright up-and-comer. But in the Paris airport of Orly, a system called DECOR — which helps air traffic controllers relay weather information to pilots — is running on Windows 3.1. That program suffered a glitch recently that grounded planes for some time. The airport actually runs on a variety of old systems, including Windows XP and UNIX. Maintenance is a problem. There are only three people in Paris that work on DECOR issues, and one of them is retiring soon. Hardware is also an issue. "Sometimes we have to go rummaging on eBay to replace certain parts," said Fiacre. "In any case, these machines were not designed to keep working for more than 20 years."