Microsoft is rolling out a new patch for both Windows 7 and Windows 8.1. The patches address some security issues. Windows 7 is approaching the end of support in January 2020. Businesses can get updates for Windows 7 until 2023 if they purchase Extended Security Updates (ESU) plan. Microsoft hasn’t disclosed the pricing yet but the cost of these patches would increase every year. Customers who purchase the Windows 7 ESU will be able to continue to run Office 365 ProPlus through 2023.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-releases-windows-7-and-81-cumulative-updates-kb4457144-and-kb4457129/